Holiday makers to Hatepe, near Taupō, are disappointed they can't swim or fish in the lake due to a toxic algal bloom.
Great Lake Taupō District Council put a note on about 100 houses at the small settlement telling them it had stopped taking water from the lake in case it was contaminated by the bloom in Lake Taupō.
The bloom has caused the council to close a number of beaches near Taupō, and the swim leg of an Ironman event being held on Saturday has been cancelled.
Gary Petersen has been coming to Hatepe for 50 years.
He drives up from Wellington often, and was looking forward to swimming and fishing until he heard about the algae.
"I'm a bit concerned as to what's going to happen over Christmas/New Year now.
"I'm extremely disappointed, all I'm looking forward to is enjoying the water.
"To be quite honest I'd love to go out for a swim right now."
Local holiday maker Gary Petersen is saddened he won't be able to enjoy the water this weekend. Photo: RNZ / Rebekah Parsons-King
Mr Petersen said if he can't go in the water he doesn't know what he will do.
He said the only communication he'd had about the water was a note on his door on Friday afternoon, and as a ratepayer he would have liked to have been more aware of what was going on.
Ironman participant Tania Wright wasn't such a fan of the swimming leg anyway. Photo: RNZ / Rebekah Parsons-King
Tania Wright and her cousin Anna Johnson travelled from Methven in the South Island to be in Taupō for Saturday's Ironman event.
Ms Johnson said she was disappointed she wouldn't be able to practice her transition from the swim to the bike, as she's using the Ironman as practise for another event in February.
"It's gutting but they can't put people at risk.
"It's a massive event, the Ironman is an international race. They're not going to throw a couple of thousand people in the water if there is a ... risk.
"It's more disappointing for those people who a year ago said 'right, I'm going to finish a 70.3 and I'm going to do it before Christmas, so Taupō's the one I'm going to do', so that for them must be so gutting."
Anna Johnson Photo: RNZ / Rebekah Parsons-King
Peter Drysdale said he'd been swimming in the lake for the past 10 days, but stopped on Friday when the message got through about the algae.
Mr Drysdale, who's been holidaying at Hatepe since 1970, said he hadn't let his dog in the water on Friday either.
He said there would be plenty of water stored in the tanks from the lake, even with the water supply from the lake cut off as a precaution.
"It's not disruptive at all, because of the reserve we have here."
Mr Drysdale said they had seen some "gunge" on the lake on Thursday night, but he had seen that before and it hadn't been a problem.
The council had taken the common sense approach by shutting off the intake of the water as a precaution, he said.
Of the 110 houses in the settlement he thought only about 15 of them would have people in them at the moment.