Treasurer Josh Frydenberg says significant funding is needed for Labor's policy as the energy grid will need to be strengthened to cope with a dramatic increase of electric cars.

But Environment Department officials on Thursday confirmed to Labor senator Kristina Keneally the government is eyeballing the same target.

Senator Keneally had to make sure: "Just so I'm clear, the government's climate solution policy includes a climate solutions package that's projecting 10MT of CO2 abatement that could come from an electric vehicle strategy that sees 25 to 50 per cent of new car sales in 2030 as electric vehicles?"

"That's right. Correct," was the reply from senior bureaucrat Kristin Tilley.

Ms Tilley also confirmed the plan for such a target hasn't been developed.

"The strategy hasn't been written as yet," she told a Senate estimates hearing in Canberra.

"The announcement was the development of a strategy which will occur."

But Mr Frydenberg had earlier taken aim at Labor's policy.

"There's going to be more demand on the grid from some of these types of reforms," he told reporters in Canberra.

"They haven't costed the backup and storage that's needed, they haven't costed what the impact on the change in the existing energy mix is."

Labor's ambitious target would be a dramatic increase on current electric vehicle sales, which make up just 0.2 per cent of Australia's market.

But the party has already been forced to change part of its policy, which originally required car dealers to lower the average emissions of the cars they sold.

Instead Labor will require manufacturers to meet vehicle emissions standards.

"Every other country in the world with emissions standards regulates this through manufacturers, not dealers," Greens senator Janet Rice said.

"This is also what the experts, including the Climate Change Authority, have always recommended."

Labor has promised to build a network of charging stations around Australia to encourage drivers to buy electric cars.

"Australia is way behind the game on electric vehicles. I mean, every comparable country is way ahead of us," shadow treasurer Chris Bowen told 3AW on Wednesday.

Motoring body the NRMA is calling for a ban on the sale of new petrol and diesel cars as early as 2025.

It's started building its own network of charging stations, with 10 already built and 30 more under way.

Australian Associated Press