Captain Sam Kerr on Wednesday said Australia were treating their opening game at the World Cup against Ireland like a final, vowing not to be overawed by playing in front of 80 000 fans in Sydney.

The co-hosts have been consistent performers on the international stage, qualifying for the Women's World Cup repeatedly since 1995.

But they have never progressed past the quarterfinals and the pressure is on, having been billed as among the favourites.

The in-form Matildas start their World Cup title charge on Thursday and star Chelsea striker Kerr said: "We are really confident, but for us it's just about the first game.

"Right now we are playing that game with no other game in mind, so that's our final at this point."

Australia will be playing against the Irish in front of a sell-out, partisan crowd at Stadium Australia.

Kerr said the team would feed off the support.

"I think everyone is looking forward to it rather than being nervous about the crowd. Everyone knows they're on our side," she said.

"It's nice when you know they're going to be cheering you on and not booing you."

IRELAND LACKING EXPERIENCE

In contrast, Ireland are at their first World Cup and head into the clash with no big-time experience.

But they will be buoyed by upsetting the Matildas 3-2 in 2021, the only time the two sides have met.

They also received a boost with experienced midfielder Denise O'Sullivan declared fit after being hurt in an abandoned friendly with Colombia last week.

O'Sullivan was rushed to hospital after a fierce tackle in a closed-doors warm-up match against the South Americans that was called off after 23 minutes with the Irish players "fearing for their bodies".

There was concern that the 102-cap star had sustained a leg fracture that could jeopardise her tournament, but coach Vera Pauw said she had made a remarkable recovery.

"We are very open, we have nothing to hide. Denise is fit, she will play," Pauw said.

Despite their worries over Colombia's physicality, captain Katie McCabe said the Irish were ready for similar treatment from Australia.

"We're Irish, we don't shy away from physicality, it's ingrained in us, the hard-working team we are," she said.

"So yes, we are ready for Australia to be physical tomorrow, we'll be prepared to match it."

Pauw admitted that Australia's greater World Cup experience could prove crucial.

But the Dutchwoman, who has previously coached the Netherlands, Russia, and South Africa, said Ireland had plenty of their own talent to trouble the hosts.

"They have huge experience, they have class players, they have immense pace so we know what we are going to face," she said.

"We are very realistic of our chances here, but we play every game to win and hope we can also show our qualities."

The 11-time African champions Nigeria and reigning Olympic gold medallists Canada are in the same group.