Australia captain Aaron Finch says he is more likely than not to play in Friday's crunch Twenty20 World Cup Super 12 match against Afghanistan, despite suffering a hamstring strain on Tuesday.

The hosts and defending champions probably need to win the Group 1 clash at Adelaide Oval to stay in the tournament and Finch said he would not risk playing if he had any doubts about his fitness.

"Very hopeful to (play), yeah. I'll have a good hit out this afternoon and give it a solid test out," Finch told reporters before training on Thursday.

"(It's) maybe 70-30, but I'll test it out properly this afternoon to make sure that I'm not hindering the side at all ... because I think the worst possible scenario is that you leave the guys short out there with one player fewer."

Tim David also sustained a hamstring issue in the win over Ireland on Tuesday and Finch said the middle order batsman was in the same position as himself.

"He's in exactly the same boat," Finch added. "He'll get worked out today, and we'll know more during training, I guess, the likelihood of both of us playing, one of us, neither of us, whatever it looks like, but exactly the same."

With one more Super 12 match to play, Australia are tied on five points with New Zealand and England at the top of Group 1 but have a far inferior net run rate - the decider for ties in the standings.

Only two teams progress from the group to the semi-finals so Australia need to beat the Afghans and give their net run rate a healthy boost or be reliant on New Zealand or England suffering upsets to get them through.

England take on Sri Lanka on Saturday, while New Zealand face Ireland in Friday's opening game in Adelaide.

The Blacks Caps have by far the best net run rate of the three sides and skipper Kane Williamson said they would be focusing purely on performance when they take on the Irish looking for a win to take them into the last four.

"We've seen the quality throughout all teams in this tournament, through the qualifiers, into the Super 12," he said. "For us it's really just continuing to focus on our cricket, trying to make those little improvements from game to game, and try and put out improved performances."

Ireland beat former champions West Indies in the first round and England in the Super 12 and, even though they and Afghanistan are out of the running for a semi-final spot, bowler Josh Little said they would be going all out for another upset.

"Everyone is pretty competitive," he said. "It's a World Cup. Anything can happen. Yeah, we're going out there fully confident hoping to get a win tomorrow."