"I was under observation for 24 hours, but released on Friday. There's no issues there."
Williams - who has been on our screens since 1979 - told the Herald in April he had upped his fitness regime after piling on a few kilos.
"I'm about two or three kilos heavier than I want to be," Williams said.
"I like to be about 84 to 85kg and I found out yesterday I'd fattened out to 87."
In 2011, the sports-mad presenter raised over $8000 for a cancer charity, after completing a half triathlon in Tauranga.
In November, explaining a plaster on his forehead, he revealed live on air he had a skin cancer removed.
Williams was due back on screen this weekend and was keen to play down the latest health scare.
"It's been a fairly busy few weeks with a few things on, so it's just a warning to take it easy," he said.
TVNZ spokeswoman Georgie Hills said Williams' week-long break was a pre-arranged holiday and that he would be back reading the news tonight.
"Peter also filmed an episode of Mastermind New Zealand last weekend and he is as fit as a fiddle."