Former F1 world champion Jacques Villeneuve has ruled himself out of appearing in the IndyCar series season finale at Las Vegas in October, despite the lure of a $5 million prize fund that is being offered to any non-series driver who can come in and take the win from under the noses of the regular drivers.

"I'm not really interested," said the outspoken Canadian. "If you can do it with a team like Penske, you know when you sit in the car and have a missile - it will be perfect," he told Autosport magazine this week. "If you do it as a last-minute, then no ... You risk killing yourself for nothing," he said, adding: "You end up doing stupid things to get the big prize."

It's believed that the deadline for expressions of interest from drivers wanting to take part in the season finale - styled as the "world championships" - passed last month. Villeneuve had previously confirmed in March that he had been in talks with IndyCar organisers about the possibility of putting his name forward.

Villeneuve - who earlier this week was outspoken about how the current DRS-era of F1 was "useless," "boring" and "not even racing" - also took the opportunity to blast the standard of driving in IndyCar, in which he competed in the 1990s before switching to F1.

"There are some great drivers in IndyCar, but there's also a bunch who should not be there," he told Autosport magazine, describing them as "Drivers that shouldn't even be in Formula 3." No names were mentioned.

The comments will have gone down badly with IndyCar Series organisers, who set up the $5 million challenge as a way of proving to the world that with its mix of road courses, street circuits and ovals, IndyCar can boast the best drivers in the world.

Instead, Villeneuve has reiterated that "My focus is on NASCAR," which he describes as "so much fun." Villenueve returned to NASCAR Nationwide racing last month at Road America, finishing third despite a late-race accident.

"It reminds me of why I got into racing in the first place. You get in the car and you are there to do your race and nothing will get in the way of that - not regulations, nothing. It's amazing. It's human against human, beast against beast. It's great. You can muscle your way through, you can work around problems - I love it!"

Among those drivers who have been rumoured as suggestions for a wildcard entry for the IndyCar Las Vegas "world championships" are former Ferrari F1 driver Jean Alesi and current WRC star Petter Solberg. Former NASCAR and F1 star Scott Speed had also been lined up for a wildcard with Dragon Racing, but the unfortunate events during qualifying for May's Indianapolis 500 might have strained that arrangement beyond repair.

Current team owners Michael Andretti and Jimmy Vasser have also been mentioned as possible entrants, and IndyCar had hoped to appeal to NASCAR stars such as Juan Montoya - although that seems very unlikely. No current F1 stars are in the running as there is a Grand Prix scheduled for the same weekend in Korea.

The exact selection criteria for who would be eligible for the five wild card slots has not been made public, with IndyCar CEO Randy Bernard saying that the decision about who would compete would be decided by a committee this summer out of all applications from interested parties.

As well as Bernard, the committee will consist of IndyCar president of competition and operations Brian Barnhart, IndyCar commercial division president Terry Angstadt, three-time Indianapolis 500 champion Johnny Rutherford and two-time Indianapolis 500 champion Al Unser Jr.

The race will be held in Las Vegas on October 16.