Should I buy travel insurance when hiring a car for a domestic road trip?

Travel insurance can be a cheaper option than a hire car excess policy, Canstar says.

Faced with a hefty excess should they have an accident in a hire car, consumers are often asked if they want to take out insurance.

Canstar says the car hire insurance excess policy can amount to hundreds of dollars, depending on the length of hire, and in many cases is not necessary as most domestic travel insurance policies provide similar protection.

The financial comparison site's editor Justine Davies said domestic travel insurance could cost as little as $60, compared to an extra $300 for car hire excess insurance she was offered at the rental counter when she recently hired a car interstate.

"For the unwary traveller, this can be a real trap, particularly when you're already standing at the counter, ready to go," Ms Davies said in a statement on Monday.

A Canstar Blue survey of Australians who had recently hired a car found the rate of accidents was 16 per cent.

AAP