Cook Islands were no match for the tournament favourites who racked up a 36-0 half-time lead before the visitors bravely dug in at a drizzling Southern Cross Group Stadium to restrict the damage after the break.

Australia named four debutants in fullback Nakia Davis-Welsh, winger Meg Ward and back-rowers Talesha Quinn and Vanessa Foliaki, and all four managed to score in their first game wearing the green and gold.

Davis-Welsh was particularly impressive, darting around like a possessed dragonfly with her explosive acceleration despite wearing several big hits including a bell-ringer from Toka Natua that left her momentarily dazed.

"I couldn't be happier that the four debutants all scored tries, that's made my World Cup already," captain Stephanie Hancock said.

"It just gives the whole squad confidence that you've got all the debutants scoring tries. I'm so proud of the girls, we've really got a point to prove this tournament."

Hancock was the only one of Australia's three co-captains to play with Ruan Sims and Renae Kunst sitting it out ahead of Sunday's showdown against England.

She played limited minutes but led from the front while she was on the field, producing a string of strong carries and laying a superb platform for her halves.

Coach Brad Donald plans to unleash a full-strength side against England on Sunday, which will include Sims, Kunst, and star fullback Sam Bremner.

Vanessa Foliaki, Kezie Apps and Karina Brown all picked up minor knocks against the Cook Islands though, and may be forced to sit out the England match.

For the Ian Bourke-coached Cook Islands, this was a watershed moment with a group of players who have been together less than a week.

Their star was Toka Natua, a powerful prop who scored three tries in the final of the women's rugby World Cup earlier this year helping New Zealand to the title.

Cook Islands captain Te Kura Ngata-Aerengamate also played for New Zealand at that tournament.

"To represent your country, your family, your ancestors, your friends on the world stage against a top team, it was just exciting," Ngata-Aerengamate said.

"We've only been together for four days, five days.

"Now we know what everyone's capable of, we know our weaknesses from that game, we know our strengths."

The Cook Islands' determination and resilience was rewarded six minutes from time when Chantelle Inangaro scored a try in the right corner.

"I know the Jillaroos wouldn't like that try, that's all they're going to think about, they won't even look at their score," Ngata-Aerengamate said.

"At the top level that I've been at, coaches always focus on what went wrong. They'll be fixing that up."

Australia started strongly on Thursday against a team that had barely trained together, and dominated the physical early exchanges, before they began piling on the points.

Halfback Caitlin Moran opened the scoring before five-eighth Ali Brigginshaw took charge, allowed to do as she pleased in directing the Jillaroo orchestra.

Brigginshaw laid on three tries and scored one herself in a first-half blitz before the Cook Islands managed to curb her influence.

She helped Brown to a try in the left corner before setting the crowd alight herself with a 60-metre run through the middle of the field, eluding several defenders en route to the tryline.

Foliaki and Isabelle Kelly also profited from Brigginshaw's sleight of hand.

The Cook Islands refused to wilt in the second half when a cricket score threatened, and Natua proved a constant thorn in the Australian side.

Their next assignment is against New Zealand, after the Silver Ferns downed Canada 50-4 in the tournament opener sowing the seeds for what looms large as a World Cup final against the Jillaroos.

Australia 58 (Moran 2, Breayley, Brown, Brigginshaw, Foliaki, Quinn, Kelly, Davis-Welsh, Ward, O'Mealey tries, Moran 3, Studdon 4 goals) Cook Islands 4 (Schofield try)