England pose 'frightening' challenge in World Cup final: Wayne Smith

New Zealand coach Wayne Smith says his team have nothing to lose when the underdogs face a "frightening" England in the women's Rugby World Cup final next Saturday.

The two heavyweights of the sport set up a showdown in Auckland but only after negotiating ferocious semi-final challenges at Eden Park.

The defending champion Black Ferns squeezed past France 25-24 and before that tournament favourites England were pushed to the limit in a 26-19 win over Canada.

It sets up a decider between the two teams who have owned the tournament silverware since the United States won the inaugural 1991 edition.

New Zealand are the holders but England have leapfrogged them as the world's top-ranked side since instituting a fully professional structure three years ago. England are on a 30-match winning run including two big wins over the Black Ferns a year ago.

A two-time men's World Cup-winning assistant coach with the All Blacks, and acknowledged as one of rugby's finest thinkers, Smith struggles to think of a greater challenge.

"Obviously I've done a lot of work on England, as all the coaches have. They're pretty frightening, they're so efficient in what they do," he said following Saturday's semi-final win.

"It's easy to say don't give away scrums, don't give away penalties, don't give away lineouts because all three or two of them, scrums and lineouts, lead to the third, which is penalties.

"So we're going to have to work out strategically how we're going to manage that."

New Zealand weren't ready for the advances made by England's Red Roses on a tour of Europe last November, hammered 43-12 and 56-15.

Former coach Glenn Moore was sacked after a damning review into the team's culture and Smith was promoted in April, initially tasked with simply restoring some pride.

They've won all 11 Tests under his watch, playing an attractive, ball-in-hand approach and have improved to the point where toppling England is a realistic prospect.

Smith says beating France was a confidence booster for his players, after the French also dismantled the Black Ferns in two lop-sided results a year ago.

"We knew that both France and England had been miles ahead of us. We've made up a bit of ground, whether we can make up some more ground over six days, I'm sure we can," Smith said.

"I'll probably be a bit freer this week, I think. I think the fact that we're in a final gives you now an opportunity to really get loose and really go for it, you've got nothing to lose."