Expansion franchises usually struggle in their first years of existence as they attempt to establish themselves and build a winning product.

The Rebels have recruited smartly during the off-season, however, and have been sweating it out on the training paddock since early October.

Macdonald said they were aiming high in their debut campaign and would catch a few sides by surprise this season.

"A lot of new teams try and develop in those first few years, but (coach) Rod (Macqueen) wants us to be competitive.

"Melbourne is the sporting capital of Australasia and they demand results."

Macdonald – who played 58 games for Southland between 2000 and 2008 – has spent the past two years with Welsh club Newport Gwent Dragons.

He has signed with the Rebels on a two-year deal and said playing in Australia would allow him to be closer to family in New Zealand.

Melbourne's opening Super 15 game will be at home against their neighbouring state rival, the New South Wales Waratahs, on February 18.

Macdonald expected there would be plenty of feeling in the game and believed a strong rivalry would develop between the two sides in the coming years.

"Everyone is looking forward to that one," he said.

"The Waratahs have set the benchmark over here. We want to start the campaign with a win and get off to a good start. We're not here to make up the numbers."

The Rebels have six locks on their books for next year's Super 15 with Macdonald likely to be vying for a starting berth with former Wallaby Alister Campbell and one-time All Black international Kevin O'Neill. Melbourne have also signed him for cover at blindside flanker should injuries strike.

Macdonald said he was loving life in Melbourne after two interesting years in the United Kingdom.

"I really enjoyed it over in Wales. It's a lot similar to New Zealand. They have a big farming community and are really passionate about their rugby.

"(The rugby) wasn't my cup of tea with the way the Northern Hemisphere game is played. It batters your body and there's a lot of games week in, week out."

Macdonald helped Southland out with their lineouts and kickoffs at training during this year's NPC, after returning from Wales.

The 32-year-old will call Melbourne home for the next two years, but would not rule out appearing for the Stags again in the future if the opportunity presented itself.

"I feel like I'm in really good shape at the moment," he said.