The Turnbull government is considering new hardline carbon-emission rules so tough it may cause the price of Australia's most popular cars to soar by thousands of dollars, according to a leading automobile industry body.

Under standards slammed by car sellers as "unrealistic and ill-considered", the government proposes to dramatically increase within eight years the cost of selling high-CO2 emitting petrol vehicles to help Australia meet its Paris climate change commitments.

If the changes proposed by the government go ahead, widely popular car models including the Toyota Hilux, Corolla, Hyundai i30 and Ford Ranger – would fall well afoul of the rules, which aim to slash the average national fleet emissions, the lobby group says.

Preliminary estimates by automobile industry experts forecasted popular models of cars could increase by more than $5000.