Reports are coming in of surface flooding on State Highway 29 and a tornado ripping through Pyes Pa.

A caller to the 0800 SUNLIVE news hotline says there was a huge downpour and then about 1pm it died down.

"The rain stopped and the wind picked up. I noticed the wind was whistling in the bathroom, thought it was odd, opened the window and saw a piece of tin flying around and some of the wheelie bins and pot plants had been lifted to the other side of the road.

"Then the wind died down again."

Two fire trucks from Greerton have been called to the scene in Pyes Pa Road, where a tornado struck a garage this afternoon.

Fire and Emergency NZ northern communication centre shift manager Scott Osmond says the garage has been demolished.

Fire and Emergency has also been notified of flooding in Henderson Crescent Parkvale, but it is not affecting property, says Scott.

Tauranga City Council says they've had a lot of calls about blocked drains, particularly in Bethlehem and Pyes Pa.

Flooding in Bethlehem.

"Flooding on the state highway roundabouts at the Lakes is being cleared now. Traffic is being managed by roading contractors," says communications advisor Marcel Currin.

"We understand that a build-up of rainwater breached through a dirt bund on an adjacent building site, which has caused the flooding on the road.

"Sediment-protection bunds are normally in place to prevent sediment draining from building sites, but in this instance the bund was overwhelmed."

NZTA says there is also surface flooding blocking the northbound lane of the SH29 roundabout.

Motorists are being advised to use extreme caution.

Tauranga Golf Course.

MetService meteorologist Tom Adams says the tornado is likely the result of earlier heavy down pours and unstable upper cold pours.

'The air is quite unstable which means there's a number of thunderstorms moving through the area.

'When you've got this instability it is possible to get very small tornadoes passing through the area.

'The heavy rain in Whakatane earlier this morning is what would facilitate a tornado if it did occur. We don't have enough information yet to say whether it did.

'Quite often tornadoes get confused for water spouts, much smaller features such as dust devils or even just large gusts of wind from thunderstorms.

'If a tornado does occur, it's unlikely for it to be too big or widespread."

He says while the chance of another tornado happening again in the next 24 hours is quite low, Bay of Plenty residents can expect similar weather moving into tomorrow.

'There is a moderate risk for thunderstorms tomorrow, so we'll see similar conditions but in any chance the risk of tornadoes is quite small.”

SH36 TAURIKO, TAURANGA - FLOODING - 1:45PM
Flash flooding has 1 northbound lane closed on #SH36 just prior to the Tauriko roundabout in Tauranga. Please take extra care, caution is required: https://t.co/MmzNoEuC1G ^TP pic.twitter.com/v4FO6qxwqO

— NZTA Waikato/BoP (@NZTAWaiBoP) May 15, 2018