No — you cannot legally convert a natural gas appliance to LPG yourself in New Zealand. This type of work is restricted work under the Gas Act 1992 and must be carried out by a licensed gasfitter registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB). Attempting it yourself is not only illegal but can be genuinely dangerous, risking gas leaks, fire, explosion, or carbon monoxide poisoning.
Why Is It Restricted Work?
Natural gas (reticulated mains gas) and LPG (liquefied petroleum gas, typically supplied in bottles or bulk tanks) are different fuels with different combustion properties. Natural gas is mostly methane and burns at a lower pressure, while LPG is propane or butane and operates at higher pressures. An appliance designed for one fuel will not work safely or efficiently on the other without specific modifications.
Because incorrect conversion can create serious safety hazards, the MBIE Building Performance and the Gas Act classify gas appliance work — including conversions — as restricted work. Only a licensed gasfitter (or someone working under their direct supervision) may legally carry it out.
What Does a Conversion Actually Involve?
A proper natural gas to LPG conversion is more involved than simply swapping a bottle over. A licensed gasfitter will typically:
- Replace the gas jets/burner orifices — LPG requires smaller orifices because it burns at higher pressure
- Adjust or replace the gas regulator — LPG regulators are set to different pressures than natural gas regulators
- Recalibrate burner air-to-gas ratios — to ensure complete, safe combustion
- Check and test all connections and seals for leaks using appropriate equipment
- Verify the appliance is approved for LPG use — not all appliances can be converted; some are fuel-specific
- Issue a Certificate of Compliance — this is a legal requirement for restricted gasfitting work in NZ
Many appliances come with a manufacturer-supplied conversion kit, but even with a kit, the work must still be done by a licensed gasfitter.
What About the LPG Supply Setup?
If you're switching from mains natural gas to LPG bottles or a bulk tank, there's additional infrastructure to consider:
- LPG cylinder or tank installation — connecting and commissioning the supply system is also restricted gasfitting work
- Regulator and pipework — must be correctly rated and installed for LPG
- Ventilation requirements — LPG is heavier than air and can pool at floor level, so adequate ventilation is critical, particularly in enclosed spaces
Your gasfitter will ensure the whole system — from the bottle or tank through to the appliance — is safe and compliant with NZS 5261 (Gas Installation), which is the key New Zealand standard governing gas installations.
Does This Require a Building Consent?
In most cases, converting an existing appliance in place does not require a building consent, as it may fall under Schedule 1 exemptions of the Building Act 2004. However, if you're changing the location of an appliance or making significant alterations to the gas supply system, a consent could be required. Always check with your local council before starting any work — rules can vary and it's not worth the risk of non-compliance.
What Can a Homeowner Do?
While the conversion itself is off-limits, there are a few things you can do as a homeowner:
- Arrange and book a licensed gasfitter — find one through tradedirectory.co.nz to get quotes from local professionals
- Contact your LPG supplier — companies like Rockgas, Elgas, or Genesis can advise on tank or bottle sizing and supply arrangements
- Check your appliance documentation — find out whether your appliance is LPG-convertible and whether a conversion kit is available
- Ensure good ventilation in the space where the appliance will be used
⚠️ Safety note: Never attempt to modify gas jets, regulators, or connections yourself. If you ever smell gas, leave the area immediately, avoid operating any switches or flames, and call your gas supplier's emergency line or 111.
How Much Does a Conversion Cost?
As a rough guide, a straightforward single-appliance conversion (such as a cooktop or heater) typically costs a few hundred dollars in labour, plus any parts. More complex jobs — multiple appliances, new pipework, or a bulk tank installation — will cost more. Get at least two or three quotes from licensed gasfitters to compare.
When to Call a Professional
You should always call a licensed gasfitter for:
- Any natural gas to LPG conversion (or vice versa)
- Installing, repositioning, or decommissioning any gas appliance
- Connecting or disconnecting gas supply lines
- Suspected gas leaks or appliance faults
- Commissioning a new LPG bottle or bulk tank system
You can verify a gasfitter's licence on the PGDB licence register before they start work. Always ask for a Certificate of Compliance on completion — this is your legal proof the work was done correctly.
Need a licensed gasfitter in your area? Search tradedirectory.co.nz to find qualified local professionals.