Rain, with heavy and possible thundery falls are being forecast for the Bay of Plenty today, with a heavy rain warning is in force for the region.

From 10am Wednesday to 7am Thursday, the MetService is forecasting 80mm to 120mm of rain to accumulate in the Bay of Plenty.

'Heavy rain may cause streams and rivers to rise rapidly,” says a post on the weather organisation's website.

'Surface flooding and slips are also possible and driving conditions may be hazardous.”

Waka Kotahi Transport Agency says SH2 is blocked eastbound prior to Pikowai Beach beacuse of flooding.

"Motorists are advised to proceed with caution and expect delays in both directions."

A state of emergency is now in place for the entire Gisborne region, Emergency Management Minister Kiritapu Allan says.

Torrential rain caused flooding, rescues and evacuations in the Tolaga Bay and Tokomaru Bay areas and closed the highway around East Cape.

A heavy rain band moving over the North Island today. Photo: MetService.

A person was rescued from their car was trapped in a river at Tokomaru Bay, where MetService says 308mm of rain had fallen overnight.

Rescue efforts were under way to free two people trapped in the water north of Tologa Bay.

Ruatoria resident John Logan had to scoop up his family in a tractor as floodwaters rose rapidly into their house. The whānau from Makarika Valley in Ruatoria near the flooded Mata River had water up to their thighs inside the home.

Gisborne Civil Defence manager Ben Green said the rainfall was a lot heavier and had come in sooner than expected. "I'd almost describe it as biblical," he says.

State Highway 35 from Gisborne around East Cape to Ōpōtiki is closed because of flooding, slips and washouts.

Rain is forecast to fall until about 10pm tonight in the Bay of Plenty. Photo: John Borren/SunLive.