Federal Environment Minister Jim Prentice said Thursday Ottawa is looking into whether to offer consumers more incentives to retire their old, polluting cars and buy new vehicles.

"We're assessing it now. Certainly any changes we make would come into effect this fall," he said in an interview with CBC Newsworld.

Last month, U.S. President Barack Obama signed his country's billion-dollar "cash for clunkers" law. Several European countries are also offering consumers financial incentives to scrap old cars and buy new vehicles.

Prentice said an existing program announced last June has not succeeded in getting as many clunkers off the road as hoped.

"We had an objective of 50,000 vehicles per year," he said. " We're currently on track to achieve about 30,000 — perhaps as much as 40,000 — vehicles."

The program — touted as a way to reduce air pollution and greenhouse gas emissions — offers incentives such as discounts on public transit passes, bicycles, memberships in car-sharing programs or $300 cash. The retired vehicles are turned over to scrapyards to crush and recycle, according to provincial guidelines.

At the time, the program was projected to cost $92 million and run until March 31, 2011.

Rebate criticized

"It's a fair question as to whether it's achieving the results we want and that's why we've been monitoring it closely," said Prentice.

He said there is roughly $64 million left in the program and that if a richer incentive were launched, it would be done with the amount of money that's already been budgeted.

Earlier this year, some auto analysts criticized the $300 rebate as too low.

Auto consultant Dennis DesRosiers said that in Germany, a similar campaign offers up to $4,500 for vehicles nine years and older.

Meanwhile, Liberal Leader Michael Ignatieff said Wednesday that retiring older vehicles is a good idea.

"Getting old clunkers off [the road] has an environmental benefit of some kind and it also stimulates demand again," he said from London, England, where he was speaking to members of Liberal International. "Encouraging demand for newer automobiles is a good idea."