Price war on car insurance Herald Sun
Meadow Heights had the biggest variation, with costs ranging from $618 to $2107 depending on the firm.
RateCity spokeswoman Michelle Hutchison said some cut-price offerings operated purely online.
More expensive premiums often featured hire cars after crashes, fast repair guarantees, new vehicle replacement and choice of repairer.
Companies controlling the $7.5 billion car insurance market have faced ramped-up competition from entrants including Kmart, Australia Post, Virgin Money and Progressive. Coles is also tipped to launch a national product.
Some major players have developed their own cheaper online offshoots.
Suncorp and IAG control about 75 per cent of Australia's car insurance market.
The RateCity check found the cheapest providers included Bingle, Youi, The Buzz and Budget Direct. The most expensive included AON, CGU, St George and Suncorp.
RateCity spokeswoman Michelle Hutchison said major car insurers had threatened legal action if league tables comparing their prices were published.