Auckland is under a state of emergency after being battered by torrential rain, with more than 230 millimetres falling yesterday.

Fire and Emergency said they received an estimated 1500 flood-related calls and power outages, cancelled public transport, events and closed roads hit Tāmaki Makaurau.

Western parts of the city are reported to be the worst affected.

Te Atatū MP Phil Twyford says in Rānui and Swanson, people had water up to their knees running through their homes.

Prime Minister Hipkins says it is an unprecedented event.

Hipkins has been with a team at the Beehive bunker overnight, and talking to the teams coordinating the response in Auckland.

He says it is difficult to get information about what is going on - but they know up to 1000 people are still stranded at Auckland Airport, and right across the region there are many people just stuck somewhere - either in their car or at an unfamiliar place.

People are being urged to call 111 if life is in danger, otherwise they should contact Emergency Management.

Auckland mayor Wayne Brown says staff will today be assessing what damage has occurred and what steps need to be taken next.

Follow the latest updates here: