The annual infestation of sea lettuce has hampered an athlete's chance at glory and there are concerns it could result in the removal of key beach events.
Mount Maunganui's pristine shoreline and blue waters were littered with green sea lettuce as more than 120 athletes competed in this year's inaugural Mount Monster.
Omanu Beach Surf Life Saving Club member and current New Zealand ironman champion Max Beattie placed second in the championship but said things could have been different if it had not been for the sea lettuce.
Mr Beattie told the Bay of Plenty Times he had to stop in the ski leg of the race to remove weed from his board, with Gisborne's Midway Surf Life Saving Club member Cory Taylor leaving him behind to take first place.
"It was really bad actually," said Mr Beattie. "I had to jump off my ski and get a handful of weed out because I was just going too slow."
Surf Life Saving New Zealand club development officer Scott Bicknell, who also competes in surf life saving sporting events, said sea lettuce was an annual problem for clubs and athletes but there was little that could be done about it.
Earlier this month, the North Island IRB (Inflatable Rescue Boat) Championships were postponed for a day and moved 800m down Papamoa Beach because the sea lettuce was too thick.
"It does cause some nightmares but we just crack on," Mr Bicknell said.
When in the water, sea lettuce binds itself to boards, fins and even people's limbs. When on shore, the green weed becomes buried in the sand and creates slippery holes for anyone running on top.
"It becomes an issue. Guys on the beach step on it and sink - when sand covers the top of it, you run on it, you sink through it. It's a bit of a challenge," Mr Bicknell said.
"We did run the surf league here. That used to be an event where the lettuce got blocked up on the boats and they couldn't go."
The league is no longer held at Mount Maunganui, for funding reasons.
Mr Bicknell said there were concerns sea lettuce could result in more events being lost from the region.
"Yes, it definitely has the potential but generally the council has been pretty good at responding to clean it up."
Bay of Plenty Tourism general manager Rhys Arrowsmith could not be reached yesterday for comment but has previously said sea lettuce has had no negative effect on visitor numbers to the region.
Tauranga City Council has already received at least eight complaints this season through the customer call centre.