Trulli finished seventh in last year's championship

The 31-year-old, who joined Toyota for the 2005 season, will next year partner Germany's Ralf Schumacher, who is under contract to the team until 2007.

Trulli's only F1 win came with Renault in 2004 and the team have struggled for form this season.

But he said: "I am 100% sure of the team's potential and its chances of challenging for the F1 Championship."

Trulli's future was unclear with his current deal due to expire at the end of the 2006 season.

I more than happy to continue my excellent relationship with Toyota into the longer term and to try to achieve our common goals Jarno Trulli

But Trulli, who has also driven for Minardi, Prost and Jordan, insists he can fufill his ambitions at his current team.

"I more than happy to continue my excellent relationship with Toyota into the longer term and to try to achieve our common goals," he said.

Toyota team principal Tsutomu Tomita said: "When you are developing a team and a car and working towards the ultimate aim of winning, it is always helpful to have continuity among your drivers.

"Jarno has played a key role in improving our performance during the two years that he has already been with us and we are delighted to continue the relationship."