As a general rule I suggest importers search for "customs broker (your city)", speaking with several companies and selecting the service that best meets your requirements.

In the case of Australian importers this could be "customs broker Brisbane", "customs broker Sydney", "customs broker Melbourne" etc. In the case of vehicles that are not being complied in your home city you may want to have the vehicle shipped to the international port nearest to the compliance workshop and engage a customs broker located in that city. While Australian customs brokers can theoretically clear any shipment in Australia in practice local customs brokers will have often have personal contacts for biological security issues, logistics, storage etc. which can be useful.