You will be required to comply with Australian Design Rule 5 if you intend to personally import a vehicle.
This Australian Design Rule (ADR) is referred to as ADR 5 Anchorages for Seatbelts. The function of this ADR is to specify requirements for anchorages for both seatbelt assemblies so that they may be adequately secured to the vehicle structure or seat and will meet comfort requirements.
Personally imported vehicles are vehicles built after 1968 that are imported by a person who owned and used the vehicle for a continuous period of at least three months before it was imported into Australia, and the person who imports the vehicle is an Australian citizen, permanent resident, or a person who has applied to become a citizen or permanent resident. The person must be old enough to hold a licence or permit to drive the vehicle, and must not have imported into Australia another vehicle that they own within the previous twelve months.
Please consult the responsible agency for more information and to ascertain the level of compliance (if any) that may be required.