Speed is thought to have been a factor in a car crash in Auckland overnight in which two people died.

A car crashed into a traffic light pole on the corner of Mt Albert Rd and Hillsborough Rd in the Auckland suburb of Three Kings, killing the driver and a passenger.

The 1995 Nissan Primera hit on the driver's side with great force about 12.30am, police said.

The front-seat passenger was wearing a seat belt but it was not yet known if the driver had a belt on, Sergeant Matthew Ford of the Auckland serious crash unit told NZPA.

But even if both were wearing seat belts it was unlikely either would have survived because of the force of the impact, he said.

Cars were not built to take high-speed, side-on crashes, Mr Ford said.

Alcohol was found in the car but it was not known yet if the driver had been drinking.

Police have one witness but were looking for others.

The names of the victims had yet to be released.