Judith Collins insists Michael Woodhouse's unverified tale of a homeless man bagging two weeks' accommodation at the taxpayers' expense is true, despite no evidence it happened.
Woodhouse, a former Minister of Health, made the claim on The AM Show last week, citing a "reliable source".
"One of the five-star hotels housed a homeless person for a couple of weeks under the pretense that it was someone who came back from overseas," he claimed, pointing to the Crowne Plaza Hotel.
"When the person was ready for discharge, he was asked for a forwarding address, only to tell the official that he didn't have one - because he was homeless."
Kiwis coming home to avoid the pandemic raging overseas have to spend a couple of weeks in a hotel, either in managed isolation or quarantine.
"He hadn't come back from overseas, he just joined the back of the queue two weeks ago, and spent a fortnight getting three square meals and a bath every day on the Government," Woodhouse said, saying it was evidence the Government's border controls were a "shambles".
The Ministry of Health investigated and found no evidence it was true, Director-General of Health Ashley Bloomfield saying on Tuesday it could be "an urban myth".
Collins said on Friday she believes Woodhouse.
"I do think it's true. Michael Woodhouse has this from a senior health professional in the area, and we back Michael because he's got this from this person. We back our people, and they tell us this is true."
Woodhouse himself admitted the claim was unverified, but said there would be "a number of anecdotes like this" and hit out at Dr Bloomfield.
"The fact that Dr Bloomfield can't find evidence that it occurred, to be honest... they can't find a lot of things right now," he told Stuff.
No other similar claims have emerged since.
There are currently 4148 people in quarantine or managed isolation, according to the Ministry of Health's latest figures.