Moving into a new home, losing a key, or ending a tenancy are all good reasons to re-key your locks. Re-keying changes the internal pin configuration so old keys no longer work — without replacing the entire lockset. It's generally cheaper than full lock replacement, and in many cases a confident DIYer can tackle it. That said, there are situations where calling a professional locksmith is the smarter (and safer) call.
What Does Re-Keying Actually Mean?
Re-keying involves disassembling the lock cylinder and replacing the small spring-loaded driver pins and key pins inside it. Once reassembled with a new pin combination, only a newly cut key will operate the lock. The lock body, handles, and hardware all stay in place — you're just changing the "secret code" inside the cylinder.
This is different from rekeying a master key system, which is considerably more complex and almost always requires a professional.
Is Re-Keying Legal for Homeowners in NZ?
Unlike electrical or plumbing work, locksmithing is not classified as restricted trade work under New Zealand law. There is no licensing requirement preventing a homeowner from re-keying their own locks on their own property. However, if you're a landlord, be aware that under the Healthy Homes standards and general tenancy law, you must ensure rental properties have working, secure locks — so any re-keying must result in a fully functional, secure lock.
If you're a tenant wanting to re-key, you'll need your landlord's written permission first.
What You'll Need
To re-key a standard pin tumbler lock (the most common type in NZ homes), you'll need:
- A re-keying kit matched to your lock brand (e.g. Lockwood, Gainsborough, or Kwikset-compatible kits available at Bunnings or Mitre 10)
- The current working key for the lock (you cannot re-key without it unless you pick or disassemble the lock — a job for a professional)
- A follower tool (usually included in the kit) to push the cylinder plug out without losing the springs
- A plug follower and pinning tray
- Needle-nose pliers or tweezers
- The new key you want to use (cut before you start)
Re-keying kits are brand-specific, so check your lock brand before purchasing. Lockwood is one of the most common brands in NZ homes.
Step-by-Step Overview
1. Remove the lock cylinder
Using your current key, turn the cylinder slightly (usually to the unlock position) and use the removal tool to push the cylinder plug out of the lock body.
2. Remove the old pins
Using the follower tool, carefully push the plug out while keeping the springs contained. Tip the old key pins out onto your pinning tray — keep track of the order.
3. Insert the new pins
Using the key code for your new key (your locksmith or key cutter can provide this, or it comes with the kit), insert the correct new pins in the correct order. The pins must sit flush with the shear line when the new key is inserted.
4. Reassemble and test
Reassemble the cylinder, reinsert it into the lock body, and test with both the old key (should not turn) and the new key (should turn smoothly).
Common Mistakes to Avoid
- Losing the tiny springs — work over a tray or towel
- Using the wrong pin sizes — always match to your specific lock model
- Skipping the test — always verify the old key no longer works before considering the job done
- Forcing a stiff cylinder — if it doesn't turn smoothly, disassemble and check pin heights
Renting vs Owning: Key Differences
| Situation | Can You Re-Key? | Notes |
|---|---|---|
| Owner-occupier | Yes | No restrictions |
| Landlord (between tenancies) | Yes | Ensure lock remains fully secure |
| Tenant | Only with permission | Get landlord's written consent |
| Body corporate property | Check rules | May require approval |
When to Call a Professional
There are several situations where hiring a qualified locksmith is strongly recommended:
- You don't have the current working key. Without it, the cylinder must be picked or disassembled — a skilled job.
- High-security or smart locks. Locks with restricted keyways, electronic components, or multi-point systems require specialist knowledge.
- Master key systems. These involve complex pin stacking and are not a DIY job.
- After a break-in or attempted forced entry. A locksmith can assess whether the lock or door frame has been compromised.
- You're unsure of the lock brand or type. Incorrect re-keying can leave your home insecure.
A qualified locksmith can also advise on upgrading to higher-security locks that meet BRANZ guidance on home security best practice. You can find trusted local locksmiths on tradedirectory.co.nz.
A Note on Security
Re-keying only improves security if the lock itself is of good quality and properly installed. If your locks are old, worn, or low-grade, it may be worth replacing them entirely. Look for locks that comply with NZS 8611 (the NZ standard for locks and latches) for peace of mind.
WorkSafe NZ also recommends that homeowners consider overall home security as part of a safe living environment — good locks are just one part of the picture.