Claire Molloy has called on Ireland's "16th player" to make the difference ahead of the World Cup opener against Australia at a sold-out Belfield Bowl on Wednesday night (7pm).

Molloy - named captain last week after the late withdrawal of Niamh Briggs due to an Achilles injury - admitted the weight of expectation any host nation carries is something Ireland will have to deal with, but she's confident they have the character and ability to use it in their favour and start with a bang.

With a partisan crowd desperate to see Tom Tierney's team go all the way, Molloy is keen to bottle that energy and blow opponents away.

"We have to deal with pressure; it's a home World Cup," she said.

"We're going to ask the girls to just focus on themselves, their own game. This is just 80 minutes of rugby. Yes, the crowd are there, and we'll use them to our advantage.

"We really need them to support us because they were our 16th player in Donnybrook against France [in the Six Nations]; that's how vital they are.

"We've got to take these negatives and make them positives on the pitch, take this pressure and turn it around back on the Aussies."

That crucial Pool C showdown with the Wallaroos has little room for error. 

France face Japan on the Billings Park pitch in UCD 45 minutes after the Irish kick off against Australia and with only the pool winners plus the best runners-up going forward to the semi-finals, a powerful start is essential.

Briggs' heartbreaking injury blow deprived Ireland of a talismanic presence, but Molloy has faith in the power of the collective.

"It's a huge blow," she said of Briggs' loss. "You don't want to see any of your team-mates suffer injury. This is sport. Unfortunately it's cruel, it doesn't take any prisoners.

"There are going to be injuries in this World Cup as well. It's a blow but we've developed a strong leadership group within the team on and off the pitch.

"There's so many people to look to. We've got to recover, move on on from it and focus on Australia. 

"They're going to be a very tough team to beat. They want to spoil the party and beat the hosts like we wanted to do in 2010 when we played England in our first game.

"We've got to be ready for it. We're well drilled, we're well prepared, we're not going to underestimate this Australia side. They're going to be very tough opposition. We can't look beyond our first performance."

"There's so many people to look to. We've got to recover, move on on from it and focus on Australia."

After Wednesday, Ireland face Japan and then France in an intense 11-day pool period. 

Goshi Arimizu's Japanese side are something of an unknown quantity for most at this tournament but Ireland did face them in two behind-closed-doors games in June.

That, along with the familiar surroundings of the UCD campus, are welcome pluses for Molloy and Co.

"They were an absolutely massive benefit," the captain said of the Japan games, which were both won by Ireland.

"We didn't know very much about Japan. Getting to play against them did them the world of good, in terms of our preparation and analysis.

At a glance: Ireland's World Cup pool rivals

"You can watch videos until the cows come home but but actually playing against a team, seeing how the players play, is the best learning experience you can have.

"It's invaluable, and obviously getting to know UCD, getting used to the facilities, getting used to the camp has made it slightly more adjustable.

"We came in on Saturday and we were like, 'we know what's going on in here'. There's no real disruption, it's very easy and invaluable experience for us."

FIXTURES

Ireland v Australia, UCD Bowl, 7pm, Wednesday 9 August,

Ireland v Japan, UCD Bowl, 5.15pm, Sunday 13 August

Ireland v France, UCD Bowl, 7.45pm, Thursday 17 August

Watch all of Ireland's games live on RTÉ Sport and the RTÉ Player (ROI only)