Mack Hansen says switching allegiance from Australia to Ireland was the best decision of his career and life as he prepares to face his country of birth.

The former Australia Under-20 player has proved a big hit for Ireland since making his debut earlier this year.

"Since I made my decision there have been no thoughts of backtracking at all," said Hansen, 24.

"I'm very happy where I am. I guess you could think what would have been with anything so no, the decision to play for Ireland has been the best decision of my career and my life.

"I'm loving it over here and enjoying it. It is still nice to hear from your peers and people back home but not once have I been upset or kind of thought 'what if?'."

Hansen, whose mother Diana hails from Cork, joined Connacht from Brumbies ahead of the 2021-22 season and has adapted seamlessly to international rugby after earning his first cap against Wales in this year's Six Nations.

He has scored three tries in eight appearances for Andy Farrell's side, including scores in the autumn Test wins over world champions South Africa and Fiji, and was this week nominated for World Rugby's breakthrough Player of the Year award.

Hansen is expected to start against a Wallabies side looking to bounce back after last weekend's shock defeat by Italy and says he is relishing the prospect of exchanging taunts with the Australian players at the Aviva Stadium.

"Whitey (Nic White) will be chirpy like always, but the rest of them aren't very witty or smart," joked Hansen.

"That's what the whole game is about. It's about going to war on the field and then afterwards just being able to have a laugh about it and be able to enjoy a quiet beer or two.

"I'm looking forward to it. It's going to be really cool. I haven't played any of these before and a lot of them are good friends of mine. It's going to be a great experience."

While Hansen says moving to Galway "wasn't like coming into a new world at all", he concedes he will be more familiar with the opposition national anthem on Saturday, prompting a plea to television crews working at the game.

"I guess it's just something I'll have to experience when it happens. I'm not sure," he admitted when asked how he will feel during the anthems.

"I'm still trying to learn the Irish one. I sing from the start and then just kind of fade away at the end.

"So if any cameraman is reading this article, film me at the very start when I'm absolutely singing the thing.

"He stopped on me for what felt like about 10 minutes last time and I didn't know it towards the end."