Wallabies back-rower Sean McMahon has all but conceded he will not take part in the 2019 Rugby World Cup and will leave Australian rugby for a two-year flexible deal in Japan.

McMahon, who has played 15 Tests for the Wallabies since debuting in 2014, has been linked to a Japanese club for some time and while there has been no official confirmation, the 23-year-old has revealed what his future holds.

"We're done with the Rebels at the end of the season and basically all I can say now is that I won't be playing in Australia next year [in Super Rugby]," McMahon said. "I'll be gone for two years. It was a very big call I've made.

"There was a few factors that came into it – a few personal ones and a few other issues I don't really want to go into. It was a big decision for my career and my personal life as well. I'm pretty happy with the decision and so is my wife. We're looking forward to experiencing something new."