Australia coach Brad Donald says leaving Emma Tonegato out of the Jillaroos squad for the Rugby League World Cup was the "hardest decision" made by selectors. 

But Donald said the omission of St George Illawarra's Tonegato — who won a rugby sevens gold medal with Australia at the 2016 Olympic Games — was an example of the NRLW's growing talent depth.

Newcastle's Tamika Upton and Sammy Bremner of the Sydney Roosters beat Tonegato to the punch as fullbacks in a strong squad that will be short-priced favourites to lift the World Cup trophy in England.

"That was probably the hardest decision for us to make and shows the quality of the women's game when someone like Emma Tonegato misses out," Donald said.

"Because of the four-day turnarounds, what we'll do is, we'll rotate a team the best we can and give everybody an opportunity to be there come the semifinals and finals."

Bremner — who was named as fullback in the Dally M team of the year and returns to international level following the birth of her child — forms part of a three-player Jillaroos captaincy along with playmaker Ali Brigginshaw and forward Kezie Apps.

The trio join Roosters centre Isabelle Kelly and Parramatta prop Simaima Taufa as the only survivors from the 2017 tournament, which the Jillaroos won on home soil.

There are 13 potential international debutants in Donald's squad, including prop Caitlan Johnston, Tarryn Aiken and Olivia Kernick, all of whom made the Dally M team of the year.