Wild weather has caused streets and houses to flood in Auckland and Northland this afternoon.
Emergency services also rescued two people who were trapped on the side of a swollen creek in Northland.
Fire communications shift manager Dallas Ramsay said since 3.30pm, they had received about 20 weather-related calls in the Auckland and Northland region.
"We're still getting calls in - but it's essentially blocked drains.
"A lot of it, there's not a lot we can do. It's just about getting traffic management there and council to unblock their drains.''
Emergency services were at Piroa Falls, in Maungaturoto, about 5.15pm where two people were trapped in their vehicle.
"[There are] two persons trapped on the other side of the swollen creek. Both are safe and well and our guys are finding options of getting them across," Ramsay said
"They've said they're just waiting until the water level goes down and then they'll walk them across.''
The pair were not in any danger.
The Fire Service was also called to ANZ building in Great South Road, in Manurewa, just before 4pm following reports of a ceiling collapse and extensive flooding at the premises.
A spokesman for ANZ said the branch was closed about 3.30pm.
"There was a roof leak - it didn't collapse - and water came in down a wall.
"Teams are working on it overnight and we hope to reopen tomorrow. No-one was hurt or put at risk."
There were no reports of injuries and everyone was evacuated from the site.
MetService has a Severe Thunderstorm Watch in place from Northland to Taranaki.
More than 200 lightning strikes have been recorded in the watch area between 3.30pm and 4.30pm.
"The line of thunderstorms is still firing up," MetService weather adviser Tuporo Marsters said.
"It's over Auckland at the moment and looks like its moving southeast towards the airport."
Clusters of thunderstorms had occurred in Warkworth and Whangarei. MetService recorded 17mm of rain at Warkworth between 1 and 2pm today.
There had also been heavy downpours in other parts of the Auckland region in the past hour, with 15mm of rain recorded at the Auckland Botanic Gardens.
The Severe Thunderstorm Watch is in place until 7pm today.
WeatherWatch head forecaster Philip Duncan said there had been "big intense downpours" in Auckland and almost no wind.
"It's been drizzly much of the day. It was always expected to intensify. The thunderstorms over Auckland have been isolated, but quite loud and dramatic.
"The worst has probably already happened but there's big clouds over Auckland at the moment so there could be another couple of thunderstorms in the next hour or two."
Further downpours were also likely in Auckland and other North Island areas up until about 6pm. After that, it would ease back to drizzle.
Thursday would be similar today, with mostly drizzly weather and patches of heavy rainfall and possible thunderstorms, Duncan said.