Crashes, power cuts as severe thunderstorm watch issued for northern NZ

Strong wind and heavy rain are causing power cuts and car crashes across Tāmaki Makaurau.

Aucklanders have faced a chaotic commute with some ferries cancelled, and crashes on the northwestern and southwestern motorways.

An amber alert is in place for the Harbour Bridge until midday, meaning speeds are reduced and lanes could close.

Auckland Transport said all Pine Harbour ferry services were been cancelled until further notice.

Vector's power outage map indicates cuts in Glen Eden, from West Coast Road extending south to Taiwini.

A severe thunderstorm watch has been issued for Auckland and Northland with bands of heavy rain and thunderstorms expected to move across Northland during the day and Auckland north of about Albany until early evening.

Some of these thunderstorms may produce downpours of 25 to 40 millimetres an hour, MetService said.

Orange heavy rain warnings are in place for Northland, Auckland, Coromandel Peninsula, Bay of Plenty west of Whakatāne and Mount Taranaki.

A number of music festivals may also be called off.

Buskers Festival managing directory Pam Glaser said cancellations would be heartbreaking as the performers have travelled from all over the world.

The Garden Music festival, Shakespeare in the Park, and the Folk festival are all still scheduled to go ahead.

MetService said winds gusting 80km/h hour are also expected in Auckland over the coming days.

The subtropical low is bringing heavy rain to Northland and Coromandel as well as Auckland.

NIWA meteorologist Ben Noll told Morning Report it may not take much rain this weekend to see issues that arose during Cyclone Hale exacerbated in areas such as the Coromandel.

Noll said some places may see up to 100mm of rain.

"Through the day today we will see it spread south, into the Waikato, Taranaki and the Coromandel - and these are places that have already seen a lot of rain so far this January."

Saturday afternoon may bring a slight window of reprieve before the rain returns on Sunday, he said.