Wellington - All Blacks coach Steve Hansen has warned against over-confidence that defending champions the Crusaders will beat the Lions in Saturday's Super Rugby final.

At a news conference on Wednesday, Hansen said the Johannesburg-based Lions, who have been beaten finalists in the last two years, have "every chance" of upsetting the Crusaders, who won the title last year for the ninth time.

"I think (Crusaders fans) need to be a bit more aware that it's only a two-horse race," Hansen said. "You've only got to think back to (the World Cup quarter-final) in 2007 in Cardiff. People didn't think that France could win and we got smacked quite badly.

"So you would expect the Crusaders to go out favourites and rightly so because they've played some wonderful football. But there's no guarantee they're going to win it. They're going have to go out and earn it and that's a pretty good Lions side, I think."

The final pits an almost All Blacks-strength Crusaders forward pack against a Lions pack which has been one of the most formidable in Super Rugby this season.

"When you look at a contest like this one you say to yourself who's going to dominate the scrums and you can't really say; who's going to dominate the lineouts and you can't really say," Hansen said. "So it's who's going to turn up on the night and get it right. Who's going to supply the right amount and right quality of ball to the backs and both backlines are quite exciting."

Hansen dampened speculation that Crusaders flyhalf Richie Mo'unga is poised to take over from incumbent Beauden Barrett for the opening Test of the Rugby Championship against Australia on August 18.

Mo'unga clearly outplayed Barrett when the Crusaders met Barrett's Hurricanes in last weekend's quarter-final. But Hansen said other factors had to be taken into account in any comparison of the players' form.

Mo'unga "is playing behind the Rolls Royce pack," Hansen said. "But, yes, he is (putting pressure on Barrett). He's playing the way we're expecting him to play behind a pack like that.

"It's going to be interesting to see how he does in a big game. It's not a test match but it's probably the closest you'll get to one without playing one. I'm really looking forward to seeing how he drives the team around the park."

Hansen said All Blacks hooker Dane Coles, who has been sidelined since November with knee and calf injuries, would make his return for Wellington province in the National Provincial Championship. Centre Sonny Bill Williams will miss the first two games of the Rugby Championship while recovering from a shoulder injury.