Carroll envisages a side in the Victorian capital could host such and outfit if member nations end player restrictions.
Currently, each union refuses to select players who extend their careers overseas.
"We need to make sure Super 14 is powering along," Carroll told The Sunday News.
"Make it an attractive competition to players, and make sure it's generating good money to pay the players' salaries.
"Expansion is something we have to consider. I don't think Australia could tolerate an extra team from our own resources.
"But that doesn't mean you can't have other teams coming in made up of players who might miss out in Super 14 teams.
"Unless we have strong competitions in the southern hemisphere, both in terms of quality rugby and strong financially, then we won't be able to retain our players."
Carroll added the Melbourne move could be a first step to allowing World Cup semi-finalists Argentina into the Super 14 and Tri-Nations tournaments.
"Their initial solution was to play in Europe but they've been rebuffed," he said.
"Does the Tri-Nations need freshening up? Yes it does. Could Argentina provide that freshness? Quite possibly yes.
"What have we got to do? Make sure the Argentinians have their best players so we've got to find a solution for that.
"It might not seem obvious, but that solution could be Melbourne."