Australia have advanced to the Perth Sevens women's semi-finals with a dramatic 24-14 win over New Zealand after both teams had a player sent off.

Reigning World Rugby women's sevens Rookie of the Year Jorja miller was dismissed after just 43 seconds following a head-on-head collision as the Kiwi attempted to make a tackle.

Australia's Maddison Levi, who was playing her first game after a three-match suspension, was red-carded for exactly the same offence just before halftime.

The host nation scored the first 12 points, conceded the next 14 and piled on the last two tries to secure a final-four berth on Sunday against the United States, who defeated France 21-5.

Great Britain shut out Canada 7-0 and in the other semi-final will play Ireland, who shaded Fiji 14-12.

Australia capitalised on their early numerical advantage over New Zealand, with tries to Faith Nathan and Madison Ashby setting up their 12-0 halftime lead.

That margin evaporated quickly with Mikaela Blyde crossing just 23 seconds after the interval.

New Zealand then hit the front after converting Blyde's second try, which was awarded despite the ball appearing to go forward off her forearm.

The Aussies hit back hard with some of their stars lifting.

Veteran Charlotte Caslick sprinted away for the go ahead try after great work from Bienne Terita and Dominique Du Toit scampered through a small gap to clinch the win.

"We've made a bit of a habit unfortunately of playing with six," Caslick told Stan Sport.

"It was a pretty gutsy performance again."

It was the first loss in 21 women's matches on Australian soil for New Zealand, completing a dark day for the sevens powerhouse after failing to make the mens quarter-finals after losing to Fiji.

Maddison Levi is expected to sit out the rest of the tournament, but her sister Teagan, who missed both of Australia's games on Saturday after getting a red card for another head collision incident on Friday, will be available if they make the decider.

The Australian men are scheduled to play the United States in the quarters later on Saturday after qualifying as one of the two best third-placed teams from the pool stage, despite losing 19-10 to Ireland earlier in the day.