Cape Town - Springbok scrumhalf Faf de Klerk says they are confident ahead of their Rugby World Cup opener against New Zealand but noted it would be a "50-50" contest.

Many pundits are saying the All Blacks are vulnerable heading into the showpiece event in Japan.

The Kiwis have lost their No 1 ranking to Ireland and finished the recent Rugby Championship in third position with only a win over Argentina.

They were held to a 16-all draw by South Africa and lost 47-26 to Australia in Perth.

The recent encounters between South Africa and New Zealand have been tight, with no more than a two-point margin between the sides in their last four Tests.

"Going into the match, both teams can win it," De Klerk told AFP on Tuesday. "We know it's going to be a tight game.

"In the last four games (between the two sides), there's been two points in it, so we're definitely confident we can win it.”

This year's draw in Wellington was preceded by a 32-30 win for New Zealand in Pretoria last year, while the Boks won the first 2018 encounter 36-34 in Wellington.

In 2017 in Cape Town, the All Blacks narrowly won 25-24, having won 57-0 in Albany in the first encounter that year.   

De Klerk added: "I think it's going to be 50-50. It's going to come down to a lucky moment or a referee call.

"We've got some confidence behind us with a few wins so hopefully we can carry that forward into the World Cup."

Saturday’s clash in Yokohama is scheduled for 11:45 (SA time).

- Compiled by Herman Mostert