When you need to secure your home after a move, a lost key, or a break-in, you have two main options: rekeying your existing lock or replacing it entirely. Rekeying is usually faster and cheaper, while replacement makes sense when the lock itself is worn, damaged, or you want to upgrade your security. Understanding the difference helps you make the right call — and spend only what you need to.
What Is Lock Rekeying?
Rekeying means changing the internal workings of your existing lock cylinder so that the old keys no longer operate it. A locksmith disassembles the lock, replaces the small metal pins (called driver pins and key pins) inside the cylinder with a new set, and reassembles it. The lock hardware — the knob, handle, deadbolt body, and strike plate — all stays exactly where it is.
The result is a lock that looks identical but responds only to a new key. This is ideal when:
- You've just moved into a new home and don't know how many copies of the old key exist
- A key has been lost or stolen
- You want all the locks in your home to work on a single key (called keying alike)
- Your lock is in good mechanical condition
Because you're only paying for labour and a small set of pins, rekeying is generally the more affordable option.
What Is Full Lock Replacement?
Lock replacement means removing the entire lock mechanism — cylinder, body, handles, and sometimes the strike plate — and fitting a brand-new unit. This is the right choice when:
- The lock is visibly damaged, corroded, or worn and doesn't operate smoothly
- You've experienced a break-in and the lock or door frame has been forced
- You want to upgrade to a higher-security lock (for example, moving from a basic knob lock to a Grade 1 deadbolt or a smart lock)
- The existing lock brand or type is obsolete and replacement parts aren't available
- You're renovating and want new hardware to match updated door furniture
Replacement costs more because you're purchasing new hardware as well as paying for installation labour.
Comparing the Two Options
| Factor | Rekeying | Full Replacement |
|---|---|---|
| Cost (as a guide) | Lower — labour + pins | Higher — hardware + labour |
| Time on site | Usually 15–30 minutes | 30–60+ minutes |
| Lock condition required | Must be in good working order | Any condition |
| Security upgrade possible | Limited | Yes — choose a better lock |
| Suits post-move security | ✓ Excellent choice | ✓ Also suitable |
| Suits damaged lock | ✗ Not recommended | ✓ Best option |
Security Standards to Consider in NZ
Not all locks offer the same level of protection. When replacing a lock, look for products that meet relevant New Zealand or Australian/New Zealand standards for locks and latches (confirm the applicable standard with your locksmith or Standards New Zealand) or internationally recognised grades. Deadbolts with an adequate throw length and hardened steel bolts are generally recommended for exterior doors — your locksmith can advise on what meets current standards. Your locksmith can advise on products that suit your door type and risk profile.
For rental properties, landlords should be aware of obligations under the Healthy Homes standards. While the standards focus on heating, insulation, ventilation, moisture, and draught stopping, ensuring tenants can secure the property is part of a landlord's general duty under tenancy law.
If you're building new or doing significant renovation work, the NZ Building Code sets out requirements for door hardware under general habitability and safety clauses. Check with your local council whether any lock or door hardware changes require a building consent — most straightforward lock swaps fall under Schedule 1 exemptions, but it pays to confirm.
Smart Locks and Modern Options
If you're considering a full replacement, it's worth exploring smart locks — keypad, Bluetooth, or Wi-Fi-enabled deadbolts that allow keyless entry and remote access. These are increasingly popular in NZ homes and can be rekeyed electronically (by changing a PIN or access code) without any physical disassembly. A qualified locksmith can advise on compatible models for your door and assess whether your door frame is suitable.
DIY or Professional?
Rekeying a lock requires a pinning kit, the correct key blank, and a fair amount of practice to do accurately. While rekeying kits are available at stores like Bunnings or Mitre 10, an incorrectly rekeyed lock can jam, fail to latch, or leave your home insecure. Full lock replacement is more straightforward for a confident DIYer if the new lock is the same size and backset as the old one — but getting the fit wrong can compromise both security and door operation.
For most homeowners, the peace of mind that comes from having a qualified locksmith do the job correctly is well worth the cost. A professional will also spot related issues — worn strike plates, a misaligned door frame, or a cylinder that's been previously tampered with — that a DIY approach might miss.
When to Call a Professional
Call a qualified locksmith if:
- You've just moved into a property and need to secure it quickly
- A key has been lost or you suspect unauthorised copies exist
- Your lock is stiff, sticky, or showing signs of wear
- You've had a break-in or attempted forced entry
- You want to upgrade to a higher-security or smart lock system
- You're a landlord needing to change locks between tenancies
You can find trusted, local locksmiths across New Zealand on tradedirectory.co.nz.
