The Ontario legislature has passed a bill aimed at reducing car insurance premiums an average of 15 per cent by next August.

The government says the bill will help tackle fraud to lower costs for insurance companies, which "is expected to help lower insurance rates for Ontario drivers."

The bill, which was supported by the Progressive Conservatives but opposed by the New Democrats, is also supposed to help those injured in collisions settle disputed claims faster.

The NDP forced the then-minority Liberal government to agree to legislate a 15 per cent cut in car insurance rates in exchange for allowing the 2013 budget to pass.

The government promised to bring the rates down an average of eight per cent in the first year, but admitted last month that so far they have seen only a six per cent decrease.

New Democrat Jagmeet Singh says insurance companies saved $2 billion a year when the Liberals changed regulations in 2010 to cut the cap on payouts for routine accident claims in half, but never passed the savings on to drivers.

The bill calls for more oversight of the billing practices of health clinics that treat accident victims, and allows only licensed service providers to be paid directly by insurers.

It also moves a dispute resolution system for injured drivers from Ontario's insurance regulator to an existing tribunal run by the Attorney General's office, which the industry has said would eliminate one step in the appeals process.