Ontario will stop giving highway contractors certain bonuses for asphalt quality after the auditor general reported some were tampering with samples.

It's one of several dozen items the Liberal government says it will address in an Action Plan for Highway Construction Contracts and Oversight released Friday.

In her annual report, the auditor general slammed the government for poor road contractor oversight, saying pavement on some Ontario roads and highways that is supposed to last 10 to 15 years starts to crack after just two or three.

She also found that the ministry was paying $8 million in bonuses each year to contractors who provide the quality of asphalt required in their contract, and bonuses even went to contractors who tampered with their asphalt samples just to get them.

Transportation Minister Steven Del Duca says the measures in the action plan will go into effect this construction season to ensure "Ontario's highway network can withstand regular use and our harsh climate."

He says Ontario will also be conducting more inspections, requiring suppliers to certify that they are providing high quality asphalt cement and creating an expert panel to advise the ministry on contract provisions.