England head coach Lisa Keightley admits the squad are still "a bit rusty" three days before the start of their Women's Ashes series against Australia in Adelaide.

The multi-format series was brought forward by a week and will start with three T20 matches at the Adelaide Oval, commencing on January 20.

England's preparation time has been dented by the mandatory 10-day quarantine required in New Zealand when they head across the Tasman for their World Cup defence in March.

This meant an earlier start to the Ashes was required and Keightley admitted it has affected the squad.

"I wouldn't say we've started that well to be totally honest, we're trying to get up to speed as best we can and we've played a couple of internal matches," Keightley said.

"We played a 35-over match after sitting around with rain for about three hours. Then we played two T20's and we lost both.

"So (we are) still a bit rusty you could say."

England have travelled to Australia looking to become the first team to beat Meg Lanning's side in any series since the 2013-14 Ashes.

This series comes after England's men's side surrendered the urn at the earliest opportunity, before succumbing to a 4-0 defeat.

Keightley is determined to help the country hit back against her native Australia.

The New South Walian added: "Australia are very excited about winning the (men's) Ashes and we've got to turn it around and try and dim the flame so to speak, get a few wins on the board and put them under pressure and get into our Ashes as quick as we can."

Australia are the No.1 ranked team in the world in One-Day International and T20 cricket and currently hold the T20 World Cup trophy. Keightley is well aware England face a difficult contest.

"I don't think any format against Australia is easy, I think they're strong in all three formats, so I don't think it really matters what we play. I think the Ashes has floated around all different formats," she said.

"We prepped for a Test match first and now we've had to flip and adapt and as staff and players we're doing that as best we can.

"But in saying that I think if we can get to that place where we want to be on Thursday and go out strong, it doesn't really matter which format it is."