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Parts of the North Island are expected to be hit by heavy rain again today, which could cause flash floods similar to the one yesterday.
Up to 28mm of rain fell in Rotorua yesterday afternoon in two hours, leaving motorists stranded in their cars, buildings flooded and emergency service workers searching for two young children who were feared to have been swept away in the floods.
Rotorua Chief Fire Officer Wayne Bedford said a member of the public called for help after seeing a young girl, believed to be aged between 10 and 12, jump into a swollen stream after dropping her cellphone in the water.
Mr Bedford said the girl was swept away but managed to grab on to something and pulled herself out before heading home, wet but uninjured.
There were also concerns for the safety of a young boy wearing a backpack who had been seen heading up a stream in waist-deep water.
Mr Bedford said a man warned the boy to get out of the water and called emergency services when he lost sight of him.
Water and land searches were launched and police appealed for any sightings of the boy or reports of missing children. By last night none had been received and it was believed the boy managed to make it home safely.
Mr Bedford said firefighters were kept busy. "It was a real flash flood from probably about 3.30pm to 5.30pm. For a couple of hours it was pandemonium."
One woman and her child had to be rescued from a car after it stalled in floodwaters.
Fire Communications Centre shift manager Jaron Phillips said the water was up to the door handles of the car when firefighters arrived to help them.
Mr Phillips said the worst flooding was in the Pukehangi area, where up to 10 homes were severely flooded by a river which burst its banks.
He said firefighters went house to house checking everyone was alright before heading off to help businesses in the city's industrial area.
Waist-deep water had flooded commercial properties and firefighters were needed to help move stock to higher ground.
MetService forecaster Andy Downs said the flash flood was caused by a slow-moving front which was heading across the northeast part of the North Island.
The front was expected to be active today and into tomorrow afternoon with further heavy rain possible in Gisborne, the Bay of Plenty, the Coromandel Peninsula, Auckland and parts of Northland.