Fernando Alonso has warned title rival Michael Schumacher he will not let up in his quest for a second world championship despite boasting an imposing advantage heading into Sunday's Canadian Grand Prix.

The Enstone-based Renault F1 team driver leads Schumacher by 23 points approaching the midway point of the season at Montreal but he has vowed not to ease off in Canada.

The Spaniard made a rare mistake 12 months ago when he hit a wall in Montreal to lose what looked like a certain victory, allowing title challenger Kimi Raikkonen to move back into contention.

He is determined to avoid giving Ferrari rival Schumacher that kind of encouragement this weekend, promising to push to the limit to keep the great German at bay.

He said: "The season is not even at the halfway stage yet and, in Ferrari, we have very strong competition.

"Last year, we were fighting against teams who had reliability problems but that won't happen with Ferrari. They will be there at every race, and very strong in Canada as well.

"So we are still attacking, still being aggressive, putting new parts on the car and trying to push the limits at every race. That's the only approach we can afford to take this season."

Montreal is a venue Alonso has been looking forward to all season as he aims to right the wrongs of previous seasons and finally stand on the podium there.

He arrives on the back of three consecutive victories five out of eight races this season and sees no reason for Renault's crushing dominance to wane on the Ile de Notre Dame.

"Canada was one of the races on my to-do list at the start of the season," he added. "I have never finished on the podium there, and that was one of my goals for 2006. So I will be really pushing to get a strong result there.

"In the past few years, this has always been a very good circuit for the Renault car.

"I didn't finish in 2005 or 2004, but we were very quick in both races, and I set the fastest lap in 2003. It will be a good track for us, I think."

Schumacher, not surprisingly, disagrees and believes Ferrari can return to the front this weekend on a track Formula One visits just once a year.

Unlike recent races at Barcelona and Silverstone, no team has had the chance to fine-tune their cars on the Montreal track and that gives Schumacher reason for hope as he seeks to claw back Alonso's lead.

"We have every reason to be optimistic," said the seven-time champion. "Our car has lived up to all of our expectations so far and we have improved it continuously.

"Nobody knows exactly what to expect because no team has tested here or any has insights.

"So everything is completely different now except our fighting spirit, which has been refreshed perfectly.

"We're ready to go and want to do well in Canada I see no reason whatsoever why we shouldn't."