A drunk driver was pulled over on Tamaki Dr and was found to over three times the limit, with three preschool children in the car.

An alleged drunk driver with three preschool children in her car was pulled over in Auckland on Wednesday night, more than three times over the legal limit.

Police were further shocked to discover two of those children, aged three and four years old, were in the middle of the back seat not wearing seatbelts, and there were also two more intoxicated adult passengers in the car.

A motorcycle patrol on Tamaki Dr pulled the vehicle over at around 10.20pm after noticing the it crossing the centre line.

Police said the only people wearing seatbelts were an 18-month-old and the woman driver, who blew 856mcg per litre of breath. The legal limit is 250mcg.

"Had our officers not intervened when they did, there's no telling how that journey might have ended for her, her passengers or others using the road," said Auckland City road policing manager Inspector Andy King.

King said police spent considerable time organising transport to get the children safely to their homes. They have been referred to Child, Youth and Family.

"It beggars belief that parents could choose to put such precious cargo as their own children in such vulnerable situations," he said.

The driver of the vehicle has been charged with driving with excess breath alcohol. One of the passengers was also arrested for obstruction.

Police say further charges are possible.