A week after the 33-year-old answered the SOS from McKenzie to join the Wallabies in camp in Perth, Mann-Rea has been retained in the training squad for Saturday's Test with Argentina on the Gold Coast.

The former coalminer was on the verge of making a remarkable international debut last weekend when he was called onto the bench for Queensland hooker Saia Fainga'a, who flew home for the birth of his first child.

Mann-Rea didn't get a run as the Wallabies rallied late to beat South Africa 24-23, but it didn't dampen what had been an amazing turn of events.

"The last week has been a great experience," Mann-Rea said.

"The start of the week, I was training with my NRC side – having my first game back from injury – then the next thing I know, I'm on a flight to Perth to train with the Wallabies for the week and then end up being on the bench.

"It was a pretty wild ride."

McKenzie called Mann-Rea last Monday morning to tell him to pack his bags and train with the Wallabies as cover for Fainga'a.

Mann-Rea took some convincing, believing he could have been the victim of a prank from his mates.

"I didn't quite know because I didn't have his number, so I had a missed call from a number," Mann-Rea said.

"[McKenzie] then texted me and said, 'I want you to come over and train with the Wallabies for the week in Perth'.

"I was wondering if it was a stitch up or the real thing.

"So I rang him, he confirmed it, and the next night I was on a plane over."

Had he played against the Springboks, Mann-Rea would have been the ninth-string hooker the Wallabies had debuted. Even at the Brumbies, Mann-Rea is considered the third-choice rake behind Wallabies captain Stephen Moore and Siliva Siliva.

But Mann-Rea has made the most of a career lifeline, standing up in just his second starting appearance for the Brumbies in this year's semi-final against the Chiefs.

Having played in Australian junior sides, Mann-Rea considered retirement before playing in Japan, then received a chance at the Waratahs in 2012.

He joined the Brumbies the following season and has recently penned a new one-year contract to remain in Canberra.

"I went to Japan because there was nothing really coming up," Mann-Rea said. "After I filled in for the 'Tahs for that bit, I thought that was going to be the end.

"The opportunity arose to come to the Brums. It's been pretty crazy.

"I've pinched myself a couple of times."

Mann-Rea doesn't know what to expect this week but will take his chance with both hands if a dream call-up to face the Pumas presents itself.

"I'm just preparing and training. If something happens like that again, you just don't know," he said.

"I wouldn't have thought I would have been on the bench last Saturday night.

"Crazy things can happen, I suppose."