UPDATED: The Rugby Union Players' Association (RUPA) has slammed a report that alleged the Wallabies were investigated for match fixing after losing a Test they were favoured to win "several years ago."

A report from the Sydney Morning Herald on Thursday night suggested that the Wallabies were investigated for match fixing several years ago and that a sporting official had recommended that investigation be re-opened.

The report alleged that there was a "deep concern" about a Wallabies loss and that there had been suspicious activity in a Test that the Wallabies were widely expected to win.

RUPA hit back at the report on Friday afternoon, describing the story as "reporting in a rumour-mongering fashion".

"RUPA is extremely disappointed by the unsubstantiated allegations raised in this morning’s Sydney Morning Herald, bringing into question the integrity of all players to have worn the Wallaby jersey," the statement read.

"RUPA remains at all times committed to ensuring the utmost integrity of all sporting contests, and as such, we implore anybody with any evidence of impropriety to immediately report it to Rugby Australia.

"If not in possession of such evidence, we ask those involved to cease slandering the names and reputation of players through reporting in a rumour-mongering fashion."

Wallabies Michael Hooper said earlier on Friday he was surprised to read allegations of Wallabies match-fixing but was confident there was nothing untoward during on in his time with the team.

"I saw that last night, bit of a shock and then I've seen Rugby Australia's comment this morning and that's put it to bed really, so not really thinking about that," he said at Friday's Waratahs captain's run.

"(I'm) not really (surprised or offended) no. It's just come out. I'm not focusing on it too much. I hope there's nothing to it."

Hooper, who made his Wallabies debut in 2012, is one of the most fierce competitors in Australian and international rugby and said he was confident none of his teammates had been involved in anything like the suggested allegations.

"You can't give more than 100 per cent. That's the way I'm built and the guys I've played with have all been cut from the same cloth and I speak on behalf of the guys I've played with for sure," he said.

There is no suggestion that any of the current Wallabies were involved in any alleged match-fixing.

Rugby Australia denied a report that the Wallabies were investigated for match fixing and that any such probe would be re-opened.

The governing body released a statement early on Friday morning, denying that any such investigation was ever conducted and said if anyone had evidence of any match-fixing they should make it known.

"A headline attached to a report in the Sydney Morning Herald today suggested Rugby Australia had investigated a Wallabies Test match “from several years ago” in relation to the possibility of match fixing," the statement read.

"Rugby Australia wishes to confirm it has seen no evidence in regards to inappropriate betting activity or match fixing and has no record of any such investigation occurring in the past.

"Rugby Australia takes any allegation of match fixing very seriously and would always thoroughly investigate should any person or entity ever provide information to the Integrity Unit."