It took the Australian outfit 12 minutes to take a 10-0 lead over Canada, but that was where the side's points ended and the North American side walked away 22-10 winners.

Saturday's loss was the second time in the Pacific Four Series the Wallaroos had been held scoreless in the second half following an early lead.

Australia took a 10-point lead in game one against New Zealand, before falling. And it happened again against Canada.

Although, it was a different story in game two in Australia's 16-14 loss to the USA, as they staged a comeback in the 59^th minute.

Wallaroos coach Jay Tregonning said there was a combination of reasons as to why his side struggled to put in a full 80-minute performance, including a new-look side lacking international experience, and a lack of international fixtures in the past two years.

"We're dying off in that back end of the games, we definitely need to work on that conditioning, and then the skills when fatigued as well," he said.

"That to me is probably not so much that we've missed out on opportunities over the last few years because the Super W season is great.

"We're in a position where we're competing with world-class teams. We need to be a bit fitter, as well as, obviously, a bit more clinical to beat these world class teams."

MORE IN CANBERRA SPORT:

The Wallaroos will return to their states and begin working on their strength and conditioning over the next seven weeks to improve their stamina.

They will need full 80-minute performances to get across the line in the O'Reilly Cup in August, and later, the World Cup.

The inability to see out the first half was where it all began at Okara Stadium. As Emily Tuttosi brought the Canadians back into the match two minutes before half-time, making it 10-7.

Justine Pelletier's runaway at the start of the second half flipped the score in the Canucks' favour, and then they sealed the deal with their third before the buzzer.

Although Saturday's loss completed a winless series for the Wallaroos, Tregonning said he could not fault the attitude and commitment of his side.

Despite giving away 18 penalties, and missing 18 tackles, the Wallaroos' defensive effort was evident by the tackle count, with more than double their opposition's at 176 to 73.

"The commitment from the team, especially defensively, is outstanding. I can't falter that," he said.

"We just need to be better at executing set piece.

"It's bitterly disappointing, and I know the players will be bitterly disappointed as well. We really wanted to get a win out of this series."

ACT Brumbies No. 8 Grace Kemp got her first taste of international rugby during her side's 12-point loss, earning her debut 51 minutes into the contest in New Zealand.

The 21-year-old helped shift the momentum in the Wallaroos' favour after her injection off the bench with a huge run down the middle of the field in Saturday's game.

But it was too late, as Canada extended their lead and clinched their second win of the tournament.