Injured Perry ruled out of Bangladesh game, expected to be fit for semi-finals

Injured allrounder Ellyse Perry has been ruled out of Australia's last World Cup group game against Bangladesh on Friday, but they expect her to be fit for next week's semi-finals.

Perry suffered back spasms and was forced from the field during Australia's win against South Africa on Tuesday. Australia's physiotherapist Kate Beerworth said Perry's back is settling with treatment.

"She won't play tomorrow but we expect that she will be available for the semi-final," Beerworth said on Thursday.

Perry was hurt when tumbling over a boundary rope in a fielding attempt against South Africa. She didn't bat as Australia banked their sixth consecutive win of the World Cup.

The Australians chased down South Africa's 271 for 5 to win with 28 balls to spare after earlier in the tournament, reeling in India's 277 for 7 to triumph with three balls remaining.

Those victorious chases, propelled by captain Meg Lanning's 97 and unbeaten 135, has further enhanced Australia's belief, spinner Jess Jonassen said.

"It's huge, particularly for our batting group," she told reporters on Thursday. "It was a really pleasing thing for our batting group to be able to go out and put a marker out there, I guess, make a statement.

"The India game got a bit closer than we would have liked...[but] coming into our last-round game and then the finals, hopefully, it gives them even more confidence in higher pressure games."

And Jonassen warned that despite Australia's perfect record in the tournament - they're the only undefeated nation - there was some improvement to come.

"It's something that we have identified throughout the whole tournament so far that we are building towards this business end of the tournament," she said. "I see Ash Gardner made the comments the other day that we're looking for the perfect game, but ultimately, we are just looking to improve every game in different areas.

"And we still have a bit to improve on, particularly with the ball. Against South Africa, we weren't able to take wickets upfront, but we were able to hold them.

"So just needing to tighten up in a few areas, which I think is really exciting considering we have gone undefeated whilst still identifying areas that we can still improve on."