Ireland captain William Porterfield is giving his side a fighting chance of upsetting Australia in their World Twenty20 Group B clash on Wednesday (2000 AEST), saying the Aussies are in a transition phase.

Ireland are ranked 10th in the world but Australia, runners-up in the previous tournament in 2010, have slipped to ninth themselves and were actually below Ireland earlier this month.

Ireland beat Bangladesh in a warm-up game in Colombo and are full of confidence with a balanced attack led by young spin sensation George Dockrell, 20.

"Irish cricket has been evolving for the past number of years and in the last five years we have been growing," Porterfield said.

"We want to get wins more regularly and this tournament is no different and that starts (today).

"We think we've got a good as chance as any (against Australia).

"We're coming up against a team that is going through a bit of transition themselves but they're a good team.

"They have a lot of lads who are game-changers especially in this format of the game, but the way we've been playing, we've prepared for this tournament and we're confident in what we can do and we're just looking after our game really."

Australia's high-profile side is led by opening batsman David Warner and Shane Watson, two of several Indian Premier League stars featured in the Aussie lineup.

The Irish in contrast have no IPL players, although they do have former Australia bowling coach Craig McDermott on their books.

"A lot of their players and a lot of their coaches are involved the IPL so that will give them a lot of experience in Twenty20 cricket in their off-season," Porterfield says.

Ireland's former NSW seamer Trent Johnston, who captained the side in their 2007 one-day World Cup upset win over Pakistan, is hoping to bring out his chicken dance again if he can claim an Aussie victim with the ball.

"We've got our plans for them but they've got quality players all the way through and we know we will have to be at our best if we are to cause an upset," the 38-year-old said.

"We're very capable of doing that."