MORE than one in three cars on Victorian roads are unsafe.

A recent survey of 2304 vehicles by the Victorian Automobile Chamber of Commerce found that 829, or 36 per cent, failed one or more of five key safety areas - tyres, lights, steering, brakes and occupant restraints.

VACC executive director David Purchase said the findings, although better than last year, were worrying.

"These defects are ones that could easily be averted," Mr Purchase said.

He urged motorists to have their vehicles checked before the holiday season.

"We are expecting an increase in traffic this holiday period, due to a combination of lower petrol prices, a slowing economy and more people holidaying nationally."

He said maintaining a vehicle not only potentially saved lives, but could save money in the long run.