Mr Thompson said there was a large amount of sea lettuce close to shore which made swimming difficult. "There is masses of it and I might get some more tomorrow," he said.
Brookfield resident Linda Thompson, who was also down at Tay St beach with her 3-year-old grand-daughter Elle-Maja yesterday, said the smell of the decaying algae was horrendous.
"I could smell it as soon as we came off the turnoff. I thought someone had slaughtered a pile of fish. It's not nice at all, it's slimy and smelly and it's hard to avoid."
"But I have also found the sea lettuce has a good side, as tangled in it were lots of gorgeous shells which we collected and I plan to make into little mice," she said.
Mitch Hoyles and his daughter Grace, 10, were also down at Tay St beach swimming.
"It makes the water all slimy and when you're swimming. It catches in your feet and hurts a bit because of the shells," Grace said.
Mr Hoyles said his wife Lisa and her step-father had been collecting sea lettuce for the garden for several years as was such a "great fertiliser".
So far the council had fielded five complaints about sea lettuce at Kulim Park and Fergusson Park, and there were also reports of weed at Papamoa and near Mount Main Beach, Mr Gardner said.
The Tay St sea lettuce problem was being monitored, he said. "Hopefully it will be carried away by tidal currents and wind in the next few days."
Mr Gardner said two harbour beach clean-ups had been completed this season.
Sea lettuce
* Is a native algae
* It grows wherever there is suitable conditions and nutrients
* The nutrients come from oceanic sources and land run-off
* People can help reduce the nutrient input to the harbour by fencing and planting around waterways
* Also be careful about what you wash down the drain
* Anyone collecting some for their garden should wash it thoroughly in freshwater
* Use it sparingly and mix it with other materials to avoid salt build-up in the soil and loss of sensitive plants
Source: Bay of Plenty Regional Council