An intriguing and slightly smelly substance washing up on the waterfront at Memorial Park has got locals turning heads.

John Stevenson, says he walks his dog in the park nearly every evening.

'We are aware there is white sea lettuce, but there is a huge difference between that and toilet paper.

'I've been having to tell people to look out for it. The smell is disgusting. After every high-tide and king tide it gets washed across into the park.

'Tourists will be playing with their kids in the playground and there will be poo in there.

'I've asked council to put signs up and to clean it up on multiple occasions. For every tourist that comes down here and discovers it the hard way, that means they will go and tell someone else, which causes a bigger problem.”

He says it's a health and safety issue.

'Council say I'm wrong. I've asked how they know this if they haven't been down to check it.

'It's been like this for ages. I grew up in this town and it saddens me that we have an indifference to dealing with issues like this.”

He'd like an open dialogue with council.

Bay of Plenty Regional Council's pollution team has responded to reports and confirmed the substance is sea lettuce.

'This is sea lettuce, which when it dries in the sun becomes white,” says communication advisor Jessica Sommerville.

In a fact sheet available on council website, Bay of Plenty Regional Council says sea lettuce can affect the way harbours and estuaries look, and also interfere with our use of the harbour.

'Over summer months of bloom years, depending on wind and tides, sea lettuce can be torn away from its growth beds and accumulate on beach and foreshore areas.

'These large accumulations of sea lettuce then rot and smell offensive because of their high sulphur content.

'Rotting sea lettuce can produce enough hydrogen sulphide gas to be dangerous to health, and shouldn't be disturbed.”

In addition seaweed can also interfere with fishing nets and lines, says council.

'Sea lettuce blooms in Tauranga Harbour are controlled by natural events and are less clearly linked to nutrient runoff from land.

'The sea lettuce blooms match the El Nino weather pattern, when persistent westerly winds drive coastal water offshore.

'In these conditions deeper oceanic water wells up to replace the coastal water, bringing with it cooler nutrient-rich water which then enters the estuaries.

'It's this increase of nutrients and the temperature reduction which is the main cause of the blooms, rather than nutrients from the land around the harbour.”

'The bloom is monitored by regional council every two months, but due to its uncontrollable nature it is deemed too costly and impractical to clean up.”

Bay of Plenty Regional Council encourages all members of public to call the 24/7 Pollution Hotline in the first instance for pollution related incidents.

For more information on Sea Lettuce visit the regional council website