Tauranga residents are assessing the aftermath after a wild night of weather from Cyclone Gabrielle.

A SunLive reader says one large "over 40m high" tree has "hit the deck" in Yatton Park, among many others across the city.

"It would have shaken houses nearby."

This comes as a national state of emergency has been declared after Cyclone Gabrielle unleashed fury across the North Island.

There has been widespread power outages, flooding, slips and damage to properties.

According to PowerCo, there are 3,631 "customers" without power in the Bay of Plenty, and 12,228 without power in the Coromandel as of 11.30am.

"In total, more than 66,000 Powerco customers have been impacted by the storm over the last 24 hours," says a PowerCo spokesperson.

Emergency Management Minister Kieran McAnulty says both the prime minister, and the Opposition spokesperson for emergency management are supportive of the move.

He says this is an unprecedented weather event impacting much of the North Island.

This is only the third time in New Zealand history a National State of Emergency has been declared.

Follow the latest weather updates on RNZ's live blog below: