Deputy Prime Minister Winston Peters denies telling Susan Devoy to lose a few kilograms during a speech made several decades ago.
Race Relations Commissioner Susan Devoy told a sports journalism awards ceremony on Thursday night that Mr Peters once said she's a "bit round" and told her to walk the length of New Zealand to lose a few kilograms.
There were "gasps from the entire audience", Newsroom's Tim Murphy wrote on Twitter.
But Mr Peters denies saying those things.
"I am aghast to read the Human Rights Commissioner's claims," he said in a written statement to Newshub.
"I never told her to 'lose weight', or that she was 'a bit round', or that she should 'walk the length of New Zealand to lose a few kilograms.'
"Dame Susan Devoy's memory is failing her. What I did say, a long time ago, prior to her walking the length of New Zealand in 1998, was meant to be a compliment.
"I said that the then Susan Devoy's sporting skill was of such a level that she could beat the best in the world even when she wasn't fit."
A corroboration of Dame Susan's story has since emerged from an unlikely source - a 2011 Stuff column from sports journalist Phil Gifford. The column places the events around thirty years ago - in the late 1980s.
In it, Gifford writes that during a prizegiving speech, Mr Peters told Dame Susan, "I have always admired enormously the fact you can win world titles while carrying so much extra weight."
The comments resurfaced when Dame Susan mentioned them during the awards ceremony on Thursday night.
"Dame Susan Devoy, Race Relations Commissioner, tells TP McLean sports journalism awards that Winston Peters is obnoxious," Newsroom's Tim Murphy tweeted.
"...that she can only be fired by the Governor-General, and that he once said of her that she was a 'bit round' and could do with walking the length of NZ to lose a few kilos... Gasps from the entire audience."
Newshub sport reporter Kirstie Stanway, who was up for an award at the event, says the content of the tweets is accurate.