The Test halfback will miss the Rebels' biggest game of the Super Rugby season next Friday night when they host Australian conference leaders NSW, with just one point separating the two teams.

Genia broke his arm in the Wallabies' second Test against Ireland in Melbourne earlier this month, requiring surgery to insert a plate.

It was his second game back after a month sidelined with a knee injury.

While Melbourne coach Dave Wessels would much prefer to have the superstar No.9 available, he's confident replacement Michael Ruru will get the job done.

"We've been playing well without Will and have won our last three games and four if you count the game against the Western Force in Perth, so Michael's earned the right to wear the jumper," Wessels said.

He said the Melbourne players who hadn't been involved in any Test matches had surprised him at training.

"It's been better than what I'd hoped for and I think it shows they're a really committed bunch who see they have the chance to do something special," Wessels said.

In their three games post the June break for internationals, the Rebels face NSW at AAMI Park then travel to play the Reds and finally the Highlanders in Dunedin.

Wessels said Genia could be available for that final match or the playoffs should his team make them for the first time.

But beating the star-studded Waratahs was the first major hurdle.

"In terms of winning the conference it's important because not only are we getting points but we're taking them away from the Waratahs," Wessels said.

Australian Associated Press