1.30pm update: Do you have a boat on Tauranga harbour? A Katikati resident has requested help with stopping blocks of polystyrene from flowing from the Uretara Stream into the harbour.

"We've tried to get as much of it as we can," says Kelli Hutchison. "But there's so much. And it's flowing down the river now out towards the harbour.

"If we could just get someone at the end of the river with a flounder net to catch it, that would be great."

A call has been made to the Bay of Plenty Regional Council Pollution Hotline and the Tauranga Harbour Master. Unfortunately at the moment, it is not possible to reach anyone at the other end. The Tauranga Coastguard has also been phoned.

Earlier, 12.55pm

Do you have a flounder net? A Katikati resident is calling for people to come and help her stop large blocks of polystyrene from being swept out into Tauranga harbour.

"The polystrene from a subdivision site in Katikati is blowing across State Highway 2 - the main road - and into the Uretara Stream," says Kelli Hutchison.

"We need as many people as possible to come right now and help us or it's going to be an environmental disaster.

"The blocks are one-and-a-half metres by one-and-a-half metres - large blocks and filling up the river."

Kelli Hutchison's children helping with collecting the polystyrene out of the river before it reaches the harbour. Photo: Kelli Hutchison.

Strong winds are causing the blocks to go into the river, as ex-tropical Cyclone Dovi cuts across New Zealand on Sunday.

Kelli is at the river with her children, trying to drag as many of the polystyrene blocks out of the river as possible.

"We just need so many people here immediately please to help. Bring a flounder net to put across the river and stop it going out into the harbour.

"It's getting worse, there's so much of it."

The polystyrene is at the northend of Katikati at the Uretara Stream.

Kelli Hutchison's son helping with collecting the polystyrene out of the river before it reaches the harbour. Photo: Kelli Hutchison.

The polystyrene blocks are being blown into the Uretara Stream in Katikati and drifting towards Tauranga harbour. Photo: Kelli Hutchison.

Photo: Linda Bonner.