Pakistan captain Shahid Afridi has vowed to unleash a surprise assault on defending champions Australia in their eagerly-anticipated World Cup Group A clash on Saturday.

"We have made some plans against them because they are very strong mentally and physically, so you will see in the game we will do something new against these guys," said Afridi on Friday.

Afridi hinted Pakistan might bring in Umar Akmal, who has recovered from a finger injury which forced him to miss the team's last match against Zimbabwe, in place of misfiring opener Ahmed Shahzad.

Both teams have a chance to top the group and face a relatively weaker team from Group B in their quarter-finals, with Pakistan on eight points from five matches and Australia nine from five.