Australia were right to relax their eligibility rules, according to Wales and Racing Metro lock Luke Charteris.
A change in policy announced in April means Australia can now select foreign-based players who have at least 60 caps and played for seven years in Super Rugby with an Australian team.
Toulon's Matt Giteau and Drew Mitchell can therefore play at the World Cup.
"If I was in charge I'd have done the same a long time ago," said Charteris. "They're quality players."
Fly-half Giteau, capped 92 times, has not featured for the Wallabies since 2011 while back three player Mitchell won the last of his 63 caps against Wales in 2012.
Australia have also called up Leinster lock Kane Douglas, a 14-cap Wallaby, to their 40-man training squad for the Rugby Championship.
And coach Michael Cheika has not ruled out a return for 111-times capped, Wasps-bound flanker George Smith.
Wales face Australia and England in Pool A at the World Cup, as well as Uruguay and Fiji, and Charteris concedes that getting out of the group will be a challenge.
"It will be tough, we knew that when the seeds were made," the former Newport Gwent Dragons player said at Wales' two-week training camp in the Swiss Alps.
"Unfortunately we were ninth in the world and that's the price you pay for it. It'll be tough for us but tough for the other teams as well."