Canada stormed into the World Cup final with a conclusive 34-19 victory at Ashton Gate but were forced to weather a second-half storm from defending champions New Zealand.

Alex Tessier's side raced 31-7 ahead with a performance that will have sent shockwaves through the women's game before displaying their mettle to withstand a determined fightback from the favourites.

England or France await in the final - the Six Nations rivals clash in Bristol on Saturday - and both will have watched the precision of their play with apprehension ahead of a possible Allianz Stadium showdown next weekend.

Six-time champions New Zealand had not lost a World Cup match since 2014, a run comprising of 18 consecutive wins, but on this night they ran into opponents who excelled in every department.

It was the Black Ferns' eighth semi-final and they had only lost once to Canada in 19 previous encounters, yet they looked like rabbits caught in the headlights as they fell 17-0 down within 24 minutes.

True to predictions of a thriller in the clash between rivals positioned second and third in the global rankings the ball was kept alive with impressive accuracy, but it was Canada who were showing the killer instinct.

First player of the match Justine Pelletier dummied her way over after Alysha Corrigan had made a penetrating run and then Asia Hogan-Rochester showed her strength to beat full-back Julia Schell in a one on one after taking a long pass.

Conceding two tries in three minutes had rattled the Black Ferns, but worse was to come.

Canada, who were winning the penalty count and collisions as well as on the scoreboard, patiently launched a series of forward drives before exploiting a huge overlap for Florence Symonds to touch down.

Stirred into life, New Zealand hit back following an athletic take at the restart by Stacey Waaka and after several forward drives Tanya Kalounivale was over.

The comeback was short lived because half-back general Pelletier weaved a path through heavy traffic before slipping a pass inside for Sophie de Goede to gallop across the whitewash.

New Zealand needed a reaction as they emerged for the second half but instead cracked for the fifth time when centre Tessier side-stepped her way over after precise build-up that included a powerful run by Hogan-Rochester.

The game looked over, but the Black Ferns finally began to look themselves as first Liana Mikaele-Tu'u went over and then Braxton Sorensen-McGee grabbed a crossfield kick by Ruahei Demant to touch down.

New Zealand were carrying with much greater ferocity and were winning the collisions, while Canada's defence began to look tired for the first time to hint at a grandstand finish.

But Canada rallied to close out the game with intelligence, De Goede adding a penalty as the Black Ferns ran out of steam.

Classy Canada cruise into World Cup final after win over New Zealand