Melbourne Rebels risk losing their fragile hold on a Victorian supporter base if they fail to overcome the loss of several high-profile stars this Super Rugby season, Tony McGahan says.

The Rebels are trying to establish a strong club culture in a saturated Australian Football league market that also boasts the consistently successful Melbourne Storm National Rugby League team, and several of their rugby rivals have predicted an improved showing this season with noted disciplinarian McGahan at the helm. But the new coach has warned of the consequences if they don't.

Melbourne have gradually improved in their three seasons of Super Rugby, but they are yet to threaten for a finals berth and they made headlines last year for the wrong reasons through big-name players Kurtley Beale and James O'Connor. The trouble-making pair have now left the Rebels, leaving the franchise with an opportunity to make a fresh start; at the same time, however, the Rebels must forge ahead without two of their most marketable and match-winning commodities.

"For us we really want to make sure we're consistent," McGahan said of his focus on attitude, self-belief and defence. "Winning our home games is the No.1 priority.

"We know there's not a lot of time and patience out there for any code or any team for that matter. We have been in the competition three years and in normal circumstances we've got longer, but we understand the market we're in. We're under no illusions we need to get results to have a team and a style of play members can identify with. And that's in a tough market down there with the Melbourne Storm who do exceptionally well."

The Rebels are undefeated in their trial matches, and Luke Burgess said that McGahan had flicked a switch in the group.

"He's not prepared to ask someone to do something he's not prepared to do himself," Burgess said. "His work ethic is incredible; I've never met anyone like him in rugby. It's pretty inspirational to hear him talk about his expectations."