Heavy rain and thunderstorms have caused flooding in the Auckland area and left two people stranded in their car by a swollen creek in Northland.

The Fire Service said the vehicle was at Waipu Gorge Road, between Waipu and Maungaturoto, and staff were waiting for the water level to go down before helping the occupants across a ford.

Among the many calls the Fire Service had received about flooding on Wednesday was one at the ANZ building in Manurewa, where there were reports of a ceiling collapse.

Spokeswoman Dallas Ramsay says firefighters were liaising with management over the best way to deal with extensive flooding there.

In the case of other calls, she said most involved getting council staff out to clear drains.