A Practical Guide for Australian Homes and Businesses
One of the most common questions we get asked is, “What’s the most secure type of door lock?”
It’s a fair question, and one we’ve been answering in different forms for almost 60 years as a business. Working as a locksmith, installing, repairing and upgrading locks across homes and commercial properties.
The honest answer is that there isn’t one single lock that suits every door, every building, or every situation. The most secure lock is the one that suits the door it’s fitted to, the risks involved, and how the property is actually used, all while being installed correctly.
This guide explains what really makes a lock secure, the secure lock types commonly used in Australia, and how to choose the right option without getting overly technical or sales-focused. I’ll also explain AS4145.2, the Australian lock standard, and why it matters.
What Actually Makes a Door Lock Secure?
Security isn’t about how expensive a lock looks, or how complicated it appears. In the real world, a secure lock usually comes down to three core things.
Solid construction and materials
Good locks are made from strong, durable materials that can handle force and long-term use. The bolt or locking tongue should be solid and well-supported, and the strike plate and door frame need to be strong enough to back it up. A high-quality lock fitted to a weak frame will never perform properly.
A locking mechanism that can’t be slipped
Many basic door latches are spring-loaded. That’s fine for internal doors, but not ideal for external security. A proper deadlocking mechanism prevents the lock from being pushed or manipulated open without the key or authorised unlocking method.
Resistance to real-world break-in methods
Most break-ins don’t involve clever lock picking. What we see far more often is:
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doors being forced or kicked
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frames being pried
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cylinders being attacked
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glass being broken so someone can reach inside and unlock the door
A secure lock either resists these attacks or makes them slow, noisy and difficult enough to discourage them.
What Is AS4145.2 and Why Does It Matter?
AS4145.2 is the Australian Standard that tests locks for security performance and durability. Locks tested under this standard are assessed against common forced-entry methods, long-term wear, and environmental exposure.
In simple terms, it helps separate locks that look good from locks that actually perform under pressure.
Locks that meet AS4145.2 are commonly rated for:
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security performance
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durability
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corrosion resistance
You don’t need to understand the technical ratings to benefit from the standard. Asking whether a lock complies with AS4145.2 is a practical way to avoid poor-quality products and focus on locks designed for Australian conditions.
Secure Door Lock Types Used in Australia
Rather than ranking locks from best to worst, it’s more useful to understand what each type does well. Each of the following lock styles has a place when used in the right situation.
Deadbolts (Deadlocks)
A quality deadbolt is one of the most effective and widely used security locks for external doors.
Deadbolts use a solid bolt that extends into the door frame when locked. Because the bolt is not spring-loaded, it can’t be slipped open. When properly installed into a solid frame, a deadbolt offers excellent resistance to forced entry.
Deadbolts work particularly well on:
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front and rear doors
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solid timber or metal doors
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doors with nearby glass
They are simple, reliable, and proven over decades of use.
Double Cylinder Deadbolts and Deadlocks
Double cylinder locks require a key on both sides of the door. This style is especially useful when there is glass in or near the door, such as sidelights or decorative panels.
The main advantage is that even if the glass is broken, the door cannot be unlocked from the inside without a key. This removes a very common vulnerability.
They do require a bit more thought around emergency exit, so they are best discussed with a locksmith to make sure they are suitable for the property and occupants.
Deadlatches
Deadlatches are extremely common in Australian homes and remain a very practical security option.
They automatically latch when the door is closed, but also deadlock so the latch can’t be pushed back. This combines convenience with strong security and reduces the chance of doors being left unlocked accidentally.
Deadlatches are particularly effective on:
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main entry doors
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homes where convenience matters
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doors that are used frequently throughout the day
Mortice Locks
Mortice locks are fitted into the body of the door itself and are commonly used in commercial buildings, apartments, and higher-end residential properties.
They are known for strength, durability, and versatility. Many mortice locks engage multiple locking points or use larger, heavier bolts than standard surface-mounted locks.
Mortice locks are well suited to:
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commercial premises
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apartment entry doors
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heritage or solid timber doors
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situations where long-term durability is important
They take more skill to install properly, but when fitted correctly, they offer excellent security.
Smart Locks and Keyless Entry Systems
Modern smart locks and keyless systems are becoming more common across Australia, and when chosen carefully, they can be just as secure as traditional mechanical locks.
Most quality smart locks still rely on a solid mechanical locking mechanism, such as a deadbolt or mortice lock, with electronic access layered on top.
Their main strengths include:
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no physical keys to lose or copy
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easy access management
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activity logs and alerts
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reduced risk of user error
The key is choosing reputable products that are designed for Australian conditions and fitted correctly.
Matching the Lock to the Door and Property
The most secure lock is not always the biggest or most expensive one. It’s the one that suits:
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the door construction
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nearby vulnerabilities like glass
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how often the door is used
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who needs access
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safety and exit requirements
In many cases, the best result comes from combining locks, such as a deadbolt with a deadlatch, or a mortice lock with controlled access.
What to Ask When Upgrading Your Locks
If you’re considering upgrading your security, a few good questions can make a big difference:
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Does this lock meet Australian Standards?
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Is it suitable for this specific door?
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Would a double cylinder be safer here?
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Can everything be keyed alike?
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Is the door frame strong enough to support the lock?
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Are there safer or more practical alternatives?
A good locksmith should be happy to explain the reasoning behind any recommendation.
Final Thoughts
There is no single “most secure” door lock for every situation. Security comes from choosing the right lock for the right door, installing it properly, and understanding how it’s used day to day.
Deadbolts, deadlatches, mortice locks and modern keyless systems all have their place. When selected thoughtfully, each can provide excellent protection for Australian homes and businesses.
If there’s one takeaway from decades in the trade, it’s this: good security is practical, not flashy. The best lock is the one you can rely on every time you close the door.