Ashleigh Gardner will miss the rest of Australia's tour of New Zealand because of a broken finger.

She suffered the injury while bowling in Australia's series-opening T20 win, Sophie Devine thumping the ball back at the offspinner.

Gardner's right index finger was fractured when she tried to snaffle the return catch in Auckland.

Follow-up scans confirmed the break.

The star allrounder is returning home to Sydney, where she will undergo further scans as Cricket Australia maps out a plan to treat the injury.

Charli Knott, an offspinning allrounder from Queensland who is yet to play for Australia in any format, has been added to the squad.

Legspinner Alana King shapes as the player most likely to replace Gardiner in the XI that defeated the hosts by eight wickets in Friday's first T20.

But Knott's call-up is an acknowledgement from selectors after an impressive summer, headlined by a player-of-the-match effort in a one-dayer at Adelaide Oval in which she scored 110 then claimed 2-37.

Australia have a chance to secure a series victory on Sunday, when the three-match T20 series continues in Tauranga.