Waterspouts have been spotted ripping through Napier amid large thunderstorms pummelling across the North Island.

Aimee Whiting noticed the waterspout - which is a water funnel resembling a tornado - from Emerson St in the town's CBD, calling it "pretty crazy".

The wild wet water was due to a low-pressure system crossing the North Island, the MetService said.

Forecasters reported showers, squally thunderstorms and hail from the Tasman Sea was due to hit in the afternoon and would likely stick around until midnight.

Just before 5.30pm, Luke Covich spotted a waterspout in Napier from Te Mata Peak.

Earlier today, a large thunderstorm was pummelling Hamilton.

Cambridge resident Cassie Jones said the "impressive" storm produced "the loudest thunder I've ever heard".

Another Waikato resident, who did not want to be named, told the Herald the lightning was "sudden and fast", like a tropical storm all packed into five minutes.

"Constant rolling thunder, then heavy lightning strikes, with one hitting the house across the road and huge loud booms that shook the house.

"Hail, heavy rain, wind ... it was like all the seasons came at once ... the thunder just continued with no break in between," she said.