Half of Australia's major car brands will be non-compliant in the first year of the government's planned vehicle emissions laws, private car market data has revealed.

The federal government wants to introduce laws that would impose an emissions ceiling on car makers, with brands forced to buy credits or pay a penalty if they exceed that limit.

With Australia decades behind other nations on introducing a vehicle emissions policy, the government wants to set the industry on an accelerated pathway to catch up with the United States by 2028.

That path would see Australia cut its emissions over three years by the same amount it will take the United States 11 years to achieve.

And most most car makers will fail to keep up with the laws, according to market analysis by Blue Flag, whose data is bought by the car brands to learn what their competitors expect to make and sell to the Australian market, including unreleased products.

Its data shows the nation's biggest brand, Toyota, would face a shortfall in the scheme's first year equating to a $1,300 impost per ute and van unless the company changed the mix of cars it plans to import and sell in 2025.

But by 2029, even after accounting for the planned introduction of EVs and new technologies, Toyota would still be facing a shortfall equivalent to a $6,700 impost per ute and van, as well as a $5,100 impost for each of its passenger cars.

Meanwhile, some makers like Great Wall Motor's will breeze through 2025 standards for their cars, but by 2029 be forecast to generate a $4,400 impost for each car.

Those imposts would have to be covered by buying credits from car brands who get under the emissions ceiling, or else be paid as a penalty — added costs that the industry says would have to be passed on.

At the government's proposed penalty rate of $100 per g/km, most car brands would be facing an additional impost of thousands of dollars for each car by 2029 without any changes to their products.

Barbara Kiss, who until last year was the director of emission compliance for General Motors in the US, said car makers have already set down their plans for next year.

"2025 is done ... this coming into play is going to cause a tear up to that, and frankly the only tear up you can do quickly here is to decide not to do something," Ms Kiss said.

Ms Kiss said while car brands would be able to shift offerings to meet emissions targets for next year, future years would need to be reached with new technologies, and those would already have to be in the pipeline to be ready for 2029.

Car companies ask to be able to spread pain over more years

Cars on average have a better fuel economy in the US, but the industry as a whole is only meeting US emissions targets by using old credits or buying more — mostly from Tesla.

And Ms Kiss noted that over the decade to 2022, as emissions rules were tightened, the average price of a car in the US rose from about $30,500 in 2012 to $48,100 in 2022, about $8,300 more than if prices had kept pace with inflation.