State Highway 25 in the Coromandel has reopened after flooding cut communities off from Whitianga this morning.
MetService meteorologist Tui McInnef said instruments at Whitianga Airport had recorded 51.8mm of rainfall in the 12 hours before 11am today while 52.1mm hit Tauranga where rain was strongest between 3am and 11am.
100mm of rainfall fell in the same period east of Tauranga, through Te Puke and a little further inland, McInnef said.
Earlier today Simpsons Bridge was impassable with flood waters turning traffic around.
Simpsons Beach resident Kate Raye said she and her neighbours had never seen flooding like this before.
"At the end of our road the bridge is completely underwater. We've been here four years and our neighbours have lived here for 30 years. We got a heavy rain warning but we didn't expect it was going to be like this."
Raye said the flooding cut the Simpsons Beach and Wharekaho community off from Whitianga and to get to shops and groceries they would need to drive half an hour to Matarangi.
"High tide isn't until 11.30am and it's still raining."
Raye said she didn't expect to be able to go anywhere until at least this evening.
Raye's advice to motorists was to avoid the area.
"Stay away," Raye said.
"We've got a lot of people driving through to have a look and getting stuck. It's creating a traffic jam."
According to Raye, if floodwaters did not recede tonight the community could face significant problems.
A New Zealand Fire and Emergency Services spokesman said there had only been one flood-related callout in the Coromandel today.
"The Whitianga brigade were called out to Wharekaho for flooding at a property."
However crews were unable to access the area, the spokesman said and would be limited in the assistance they could provide.
"If the flooding is inside a house from a burst pipe we could pump the water out," the spokesman said.
"But if the water's knee deep inside and outside there's not much we can do."
The spokesman said the fire crews would need to wait for the water levels to go down.
Waka Kotahi NZTA Waikato System Manage Cara Lauder said floodwater at Simpsons Bridge was 1m deep at 11.30am.
'It has now stopped raining and flood waters are rapidly receding. We expect the road to be clear of flood water around 1pm.
"Driving through flood waters is not safe, as we can't confirm what is below the surface. There could be washouts, collapsed culverts, debris etc.
"Other Coromandel locations that typically saw flooding during heavy rain had not had any issues," Lauder said.
A severe thunderstorm watch was in place for Bay of Plenty, Rotorua and Coromandel until 5pm today.
Bay of Plenty Civil Defence has warned the public to expect "periods of heavy rain with a risk of localised downpours of 25mm to 40mm per hour and thunderstorms."
MetService said a frontal system is expected to cross the North Island today, bringing a period of heavy rain.
Surface flooding was also reported in Tauranga this morning.
Tauranga City Council has reopened the Te Ara Tūtanga (Mauao base track) and Moturiki (Liesure Island),
It earlier closed the base track from 9.30am and Moturiki from 10.45am due to high swells.