Land Transport Act 1998, ss 122, 123
The police can seize and impound vehicles for up to 12 hours in an emergency involving public safety. They can extend this for up to another 12 hours if they believe this is necessary.
The police can also impound vehicles for up to seven days when there’s been a serious traffic accident or hit-and-run offence or when the driver has failed to stop for the police, if impounding the vehicle is necessary to preserve evidence or establish the cause of the accident. (A “serious” traffic accident is one where someone is injured or killed.) The District Court can extend the impounding period for up to another seven days, and can later renew any extension it has given.
In some situations, the police are required to seize and impound your vehicle for 28 days – for example, if you’re driving while disqualified, see “Losing your vehicle: Impounding and confiscation” in this chapter.