Yes — having multiple locks operate from a single key is absolutely possible, and it's one of the most popular services NZ locksmiths offer. The process is called key-alike rekeying (or, in more complex setups, master keying), and it can save you the daily frustration of juggling a bulging keyring.
What Is Rekeying?
Rekeying means changing the internal pin configuration of a lock cylinder so it responds to a different key — without replacing the entire lock hardware. A locksmith removes the cylinder, replaces the driver pins and key pins inside to match a new key cut, and reassembles everything. The lock body, handles, and deadbolt all stay in place.
This is different from replacing a lock, which involves fitting entirely new hardware. Rekeying is generally faster and less expensive.
Key-Alike vs Master Keying — What's the Difference?
| Term | What it means | Typical use |
|---|---|---|
| Key-alike | All locks share one identical key | Home with multiple entry doors |
| Master keying | One master key opens all locks; individual keys open only their own lock | Rental properties, small businesses |
| Grand master keying | Multiple levels of access in a hierarchy | Large commercial buildings |
For most NZ homeowners, key-alike is the goal — one key for the front door, back door, garage entry, and any other external locks.
Can You DIY Rekey Your Own Locks?
Some lock brands sell DIY rekeying kits — Kwikset's SmartKey system is a well-known example internationally, and similar products appear at stores like Bunnings and Mitre 10. These kits let you rekey certain locks at home using a special tool and a new key.
However, there are real limitations:
- Brand and model specific — kits only work with compatible lock cylinders. Most NZ homes have a mix of brands (Lockwood, Gainsborough, Whitco, Assa Abloy), and not all support DIY rekeying.
- Skill and tools required — working with small pins and springs is fiddly. A mistake can jam the cylinder or leave the lock inoperable.
- Key-alike across different brands is very difficult — matching pin configurations across locks from different manufacturers is essentially impossible without professional equipment and a key-cutting machine.
- Security risk — an incorrectly rekeyed lock may be easier to pick or bypass.
Bottom line: DIY rekeying one lock of the same brand to a new key is feasible for a careful, patient homeowner. Rekeying multiple locks — especially of different brands — to a single key is a job for a qualified locksmith.
What a Locksmith Does Differently
A professional locksmith has pinning trays, plug followers, a key-cutting machine, and a stock of pins in all sizes. They can:
- Assess whether your existing locks can be rekeyed or need replacing
- Rekey cylinders from different brands to a common key cut
- Cut new keys on the spot
- Advise on upgrading to higher-security cylinders (look for locks rated to AS/NZS 4145 for residential security)
- Set up a master key system if you need tiered access (e.g., for a rental property)
A good locksmith will also check that your door frames, strike plates, and deadbolts meet a reasonable security standard — useful peace of mind alongside the rekey.
How Many Locks Can Be Keyed Alike?
In theory, there's no hard limit. In practice, most residential properties rekey two to six external locks to a single key. The more locks involved, the more important it is that the cylinders are compatible — your locksmith will advise if any locks need to be replaced rather than rekeyed.
What About Rental Properties?
If you're a landlord, the Healthy Homes Standards don't specifically mandate lock types, but you do have obligations around security and weathertightness. Rekeying between tenancies is considered best practice — it ensures previous tenants (or anyone they gave a key to) can no longer access the property. A locksmith can rekey all locks and provide a set number of new keys for incoming tenants.
Approximate Cost Guide
As a rough guide only, NZ locksmiths typically charge a call-out fee plus a per-cylinder charge for rekeying. Costs vary by region, lock type, and number of cylinders. It's worth getting two or three quotes — you can find qualified local locksmiths on tradedirectory.co.nz.
When to Call a Professional
Call a qualified locksmith if:
- You want two or more locks keyed to the same key
- Your locks are from different brands or models
- You're setting up a master key system for a rental or small business
- A lock is damaged, stiff, or has been tampered with
- You've just moved into a new home and want to ensure no old keys are floating around
- You're unsure whether your locks meet a reasonable security standard
Locksmithing is not legally restricted work in the same way as electrical or plumbing, but it does require skill and the right tools. A botched rekey can leave you locked out or with a compromised lock — so for anything beyond a single compatible DIY kit, a professional is the smart call. Find a trusted local locksmith on tradedirectory.co.nz.
