Australia will be without Sharni Layton for this year's netball tests after the young defender succumbed to a shoulder injury.

Layton will undergo surgery to repair damaged ligaments in her left shoulder and will miss all nine of Australia's upcoming tests.

The 24-year-old Adelaide Thunderbirds' star debuted for Australia last year and has gone on to make nine appearances for the Diamonds - including a part in last year's world championship win.

She said it was a tough call to opt for the surgery but one that had to be made following consultations with the team's medical staff.

"To represent your country is an honour and it's something that I've worked really hard towards this season, so not to be able to trial for selection is heartbreaking," Layton said.

"It was a really difficult decision to make.

"I didn't want to accept the extent of the injury because I could keep playing with it strapped but, with the instability, I can't risk it.

"I could end up doing twice as much damage if it popped out."

Australia's 22-player squad continued a four-day selection camp in Canberra on Thursday as they battle for spots in coach Lisa Alexander's final group for the upcoming tests.

The Diamonds take on traditional rivals New Zealand in a three-test Constellation Cup series in September while six more tests follow in October in a four-nation series against the Silver Ferns, England and South Africa.

Alexander said Layton's news was a personal blow but hoped she would make a full recovery.

"She's devastated but she knows she needs to get it right and it's important for her longevity as an athlete to get her shoulder right," Alexander said.

The Diamonds are expected to announce a final squad for the tests on Saturday.

- AAP