Payne Haas has revealed the moment he knew it was time to represent Samoa, the country of his mother's heritage, ending his international career with Australia after four Tests.

Speaking on Sunday morning in Brisbane, following his unveiling as Samoa's newest international representative, Haas recounted a defining moment while playing for Australia against Samoa in Townsville that cemented his decision.

"There was a moment when I was playing for Australia against Samoa in Townsville. The anthems were playing and my mind started racing back to lots of memories with my mum and us singing the national anthem in the back of the car," Haas said.

"From that moment onwards I wanted to play for Samoa and represent my mum's side, the Taufua side, and really make them proud, as grandparents as well.''

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"It means a lot to me. I was grateful to be able to pull on the (Australian) green-and-gold jersey. But I think the time is right for me to represent my family, my mum.''

The 25-year-old revealed that his first assignment for Samoa will be the Pacific Championships, taking on New Zealand and Tonga at Suncorp Stadium on October 26.

Haas said his desire to represent Samoa was also inspired by watching his uncle, former NRL player Mark Taufua, perform the traditional Sipi Tau war dance before games during the 2013 World Cup.

"So I get my moment now to play for someone I've always wanted to play for," he said.

The star forward also joked about reuniting with his uncle, who remains involved with the team as "the world's oldest water boy.''

"I love my family and it is going to be good to be around my uncle again. Hopefully he does not pull a hamstring,'' Haas said.