Australia captain Sam Kerr has declared herself available for the co-hosts' must-win Women's World Cup clash against Canada on Monday after a calf injury.

The prolific striker missed their opening two matches as Australia beat the Republic of Ireland 1-0 but then lost 3-2 to Nigeria in a blow to their hopes of reaching the last 16.

"I am going to be there, I am going to be ready," Australia's star player told reporters in Brisbane, declining to say exactly how much of a part she will play.

"I feel good, the plan has always been the same -- miss the first two games and then reassess," said the Chelsea player. "So I feel good, I was out on the pitch today, as good as I can be."

Australia fans will be desperately hoping that Kerr can start the game in Melbourne against Olympic champions Canada, but the 29-year-old refused to confirm how long she would be able to play for.

The shock defeat to Nigeria left Tony Gustavsson's side needing to beat Canada to be sure of avoiding an unthinkable group-stage exit from their home tournament.

"I would love to tell you guys everything but you know being in sport a long time that that's a massive thing that the opposition wants to know," Kerr said.

"It is going to go down to the wire. I am definitely going to be available but how we decide to use that is not to be given to the opposition."

Kerr suffered the calf injury on the eve of her team's opening game and her absence has been a major hit to the co-hosts. They were reduced to the bare bones in attack for the Nigeria match on Thursday, which Mary Fowler also missed due to concussion.

"I have never had an injury like this in my career. Touch wood this is the last," Kerr added. "It was obviously disappointing but I had to suck it up. I am part of a team, it's not about me, and that is what I have done." She sought to put the injury into perspective after seeing Keira Walsh come off on a stretcher with a potentially serious knee injury during England's game against Denmark on Friday.

"I look around women's football at the moment and I am lucky it is only a small injury compared to some other people, you look at Keira Walsh last night," said Kerr. "It kind of sucks but there is always someone worse off."

Kerr added that she has found it difficult adapting to a new role of cheering on the team from the sidelines. "I definitely get much more nervous sitting on the bench when it's out of my control," she said. Canada will be through with a draw in the Group B finale.

A draw would only suffice for Australia if Nigeria lose to Ireland at the same time and goal difference swings in favour of the Matildas.