Ref whistles a warning for Black Ferns

New Zealand will need to swot up on their rule books if they hope to unleash their full potential against England in the final of the women's rugby World Cup on Sunday.

They earned a shot at defending their title when they ground out a 30-0 semifinal win over France in sapping heat at Cornella, Barcelona, yesterday.

England had earlier scored an emphatic 53-10 win over Canada.

For the second match in a row, an impressive forward effort backed by good positional kicking kept the Black Ferns camped in their opponents' half for most of the match.

The pressure resulted in four tries, and fullback Tammi Wilson added two first-half penalties.

Wilson and blindside flanker Melodie Robinson both crossed in the first half, and replacement winger Dianne Kahura scored with her first touch of the ball late in the second spell.

She then slashed through the defence on a 50m run which was eventually finished off by prop Rebecca Luia'ana.

But the match did not look safe for the New Zealanders until their two late tries. They proved their own worst enemies by conceding a string of momentum-breaking penalties that kept the beleaguered French afloat.

Cheryl Waaka, a standout performer for New Zealand with inspirational captain Farah Palmer, lineout star Victoria Heighway and the flying Kahura, admitted that the team were slow in adjusting to referees working to the letter of the law.

"The referees are being strict on the breakdown and we're getting penalised for things that we can get away with all the time at home," said Waaka, who had few complaints about the consistency of the rulings.

"I guess we're being slow to adjust, but we better get it sorted out before the final if we want to play to our potential."

Coach Darryl Suasua was far from happy with his side's ill-discipline, especially as they were reduced to 13 players for two minutes in the second half when flanker Adrianne Lili'i and winger Amiria Marsh were both sin-binned.

"At halftime I was full of praise for their discipline because it was very frustrating stuff," he said.

"Every second play the French were going down with an injury or a bootlace, so it was very stop-start, but then we had those two silly moments in the second half, which was very disappointing.

"We gave away a lot of penalties, especially at the breakdown. We were going off our feet and it seemed that whenever we did get some momentum we got pinged, so we're going to have to get that right."

Waaka, who was switched from blindside to No 8 after Rochelle Martin was suspended for the match, showed her ability to get across the advantage line off the back of the New Zealand scrum.

The former winger, who switched to the forwards after the last World Cup, also made some telling contributions in open play and admitted she had enjoyed the extra freedom of playing at the back of the scrum.

"I was given the freedom to play the game the way I like to play it, and I've always been able to kick, so it was good to turn them around by kicking in behind them a couple of times," said the 32-year-old Aucklander.

"The French did anything in their power to upset us. They were going down with injuries every two seconds and they collapsed every maul we got going.

"We were pretty patient, even though we couldn't get on a roll. I think we all wanted to do more.

"But we did open things up in the last 10 minutes, and at the end of the day we still scored four tries and won 30 points up."

With the final only four days away, Waaka felt the New Zealanders were "90 per cent there".

The New Zealanders have played three games without conceding a try, a single penalty goal from Australia being the only points scored against them in the cup.

The final will be played in the Olympic Stadium complex in Barcelona.

New Zealand 30 (T. Wilson, D. Kahura, M. Robinson, R. Luia'ana tries; Wilson 2 pen, 2 con) France 0.

- NZPA