Centre Paddy Wallace admits Ireland are unsure how Australia will play under new coach Robbie Deans when the two teams meet in Melbourne on Saturday.

After leading the Crusaders to five Super rugby titles in the past nine seasons, New Zealander Deans took over from the outgoing John Connolly last month and will make his coaching debut against Ireland this weekend.

Deans has promised that his side will play attractive rugby, attack throughout and score plenty of tries, but Wallace said the Irish were in the dark as to how the new-look Australian team would play.

"We don't really know how they will come out because they have a whole new coaching staff,'' Wallace said.

"You take what you can out of the Crusaders out of the last six, 10 years when he has been in charge.

"From the personnel they have picked they have got (Berrick) Barnes at 12 and I am sure they will play a lot off him at second receiver and we will need to keep him quiet.''

After scoring Ireland's only try in the 21-11 loss to New Zealand last Saturday, Wallace will be looking for another strong performance against the Wallabies to cement his spot in the starting XV.

Wallace generally plays fly-half for Ulster but interim Ireland coach Michael Bradley has given the 28-year-old a chance to impress in the number 12 jersey against Australia.

"They have given me an opportunity to show that I can play somewhere other than the 10 and that I can play 12 as well,'' Wallace added.

"Conditions probably didn't suit my game last week and hopefully under the closed roof at the Dome it will suit my style of play.

"I think it is going to be a very high tempo match for both teams and I am sure it will be a joy to watch and an entertaining game. I am really looking forward to it.''

Wallace knows that his side will need to play better than they did last week and that they will need to play a full 80 minutes of rugby if they are to win for the first time on Australian soil since 1979.

"We have to cut out those small errors that end up costing you points and tries,'' Wallace said.

"Last week we gave up some cheap penalties that allowed New Zealand to keep the scoreboard ticking over so they are a couple of areas we need to improve.''