There had been a complaint in 2013 about cattle in the lake, he said.
Environment Canterbury had spoken to the farm manager at the time to prevent stock entering the lake again. No fine was imposed.
Mr Fletcher, a former chief executive of Fletcher Challenge, told RNZ yesterday Lake Taylor was fenced off from his cattle at Lakes Station, but he did occasionally let them into the lake for a drink on hot days.
The photograph sparked a war of words between Canterbury's Federated Farmers and Fish and Game.
Federated Farmers North Canterbury president Frank Brenmuhl said the situation wasn't ideal, but the environmental effects would probably be minimal.
"What we're looking at here, as far as I can tell, is high-country cattle drinking in a high-country lake," he said.
"It's not common, the stocking rate is very low, the impact is also very low."
But Fish and Game communications manager Don Rood said the comments were irresponsible, Mr Rood said, and that the situation is a big deal to locals.
The person who took the photograph is laying a complaint with Environment Canterbury.
Mr Rood said Fish and Game would also want to take the matter further.
The organisation posted its disgust to Twitter, saying: "Is this good enough? Cattle get free access to Canterbury's beautiful Lake Taylor beside DoC's public camping ground."
The tweet has become Fish and Game's most popular.
Property owners in the Lake Taylor area are also defending farmers who let their cows bathe in the waterways.
Chris Shucker, who owns a bach in the area, said humans did more damage than the cows could.
"All the campers still leave their rubbish, their crap in the bush and leave a hell of a mess everywhere," he said.
But the Green Party said mixing cows and fresh water is a recipe for pollution.
Greens water spokeswoman Catherine Delahunty said it was an affront to locals and tourists who have an interest in keeping the water clean.
"Everywhere in this country where there's water, it needs to be protected, not only in our most popular recreational spots like Lake Taylor, but everywhere because fresh water is declining fast."
Keeping cattle out of waterways is common sense, Ms Delahunty said, and should be legislated to protect and secure clean fresh water.
Land Information New Zealand said it would remind visit farm owners on either side of Lake Taylor today to remind them about their obligations.
The Law Society said it had no comment to make on the matter.