Alternative fuel certificates

Vehicles powered by liquefied petroleum gas (LPG) or compressed natural gas (CNG) must undergo additional checks to ensure the fuel systems are safe. These additional inspection requirements apply before the first use of the vehicle with the system fitted, and then annually once in use.

Installing an LPG or CNG system in your vehicle

If you want to install an LPG or CNG fuel system in your vehicle, the system must comply with an approved standard:

We recommend that you have the system installed professionally. And, before you can use your vehicle, you need to obtain:

  • an alternative fuel installation certificate, and

  • an alternative fuel inspection certificate.

Most professional installers are authorised by Waka Kotahi NZ Transport Agency to issue these certificates.

Getting an installation certificate

Once the LPG or CNG system is installed, an authorised vehicle inspector must inspect the vehicle to ensure that the LPG/CNG system meets the required standards. The inspector will then certify the installation and issue you with an installation certificate.

The standards also require an installation compliance plate for each LPG/CNG container. These plates are attached to the inside of the engine bay.

Getting an annual inspection certificate

The inspector will also issue you with an inspection certificate – this is valid for one year. As long as the LPG/CNG system remains in working order, regardless of whether you actually use the system, you’ll need to obtain a new inspection certificate every 12 months.

For each annual inspection, you need to present your installation certificate. The inspector will carry out detailed safety tests and inspect the system components to ensure they are safe before issuing another inspection certificate.

Alternative fuel system certification information(external link)

Your vehicle cannot pass a warrant of fitness (WoF) or certificate of fitness (CoF) inspection without a current alternative fuel inspection certificate. The WoF or CoF inspector will also carry out a basic check of the system to ensure there are no obvious leaks or loose components.

Warrant of fitness (WoF)

Certificate of fitness (CoF)

WoF and CoF requirements for LPG and CNG systems(external link)

You must not fill up the LPG or CNG system unless the vehicle has a current inspection certificate.