Modelling for the Morrison government’s climate policy assumes electric vehicles will make up between 25% and 50% of new car sales by 2030, a similar figure to the target set by the Labor party, which the Coalition criticised this week.

Labor’s climate spokesman, Mark Butler, said “it shows how out of touch the Liberals are even with their own department” when it comes to cutting carbon pollution from transport.

Labor’s climate policy, announced this week, included a target for 50% of new cars sold by 2030 to be electric.

The government has said Labor’s reforms could prove costly – the environment minister, Melissa Price, said the party’s stance on electric cars “lacks any credible planning or detail to back up its target”.

The Morrison government’s electric vehicles policy has not yet been written but Price said the Coalition was aiming for “25% +” of all new vehicles to be electric by 2030.

The environment department told estimates hearings that projected emissions cuts of 10m tonnes through the government’s proposed electric vehicles strategy were based on data indicating electric cars could account for 25-50% of new sales by 2030.

The projection, contained in the climate solutions package, was drawn from data prepared for the Australian Renewable Energy Agency and the Clean Energy Finance Corporation by consulting firm Energeia.

“That analysis indicated that electric vehicles could make up between 25 to 50% of new car sales in 2030 if supported by coordination and facilitation of local state and commonwealth actions coordinated through a national strategy,” Kristin Tilley, the first assistant secretary of the department’s climate change division, told the hearing.

“Just so I’m clear, the government’s climate solutions policy includes a climate solution package that’s projecting a 10 mega tonnes CO2 abatement number that could come from an electric vehicle strategy, that sees 25 to 50% of new car sales in 2030 as electric vehicles?” the Labor senator Kristina Keneally asked.

“That’s right” officials said.

Officials told the hearing the government’s electric vehicle strategy hadn’t been written and the announcement in the climate solutions package was that one would be developed.

This week’s budget included $400,000 for its development, something that could take until mid-2020.

“The hard-right of the Coalition have strangled any effective climate change policy,” said Butler.

“That’s why the Liberals don’t have a transport emissions policy, just like they have no broader emissions reduction policy.

“A Shorten Labor government will work with Australia’s transport sector to cut vehicle emissions, boost adoption of electric vehicles and help Australians save on their petrol bills.”

Labor’s policy also includes a proposal for vehicle efficiency standards, which it originally proposed to impose on car retailers.

But it changed course this week and instead will require this of car manufacturers, similar to other countries.

Price said the “embarrassing backflip” suggested a lack of planning in the policy.

“Rapidly increasing the number of electric vehicles on the road requires a plan for a multi-billion dollar investment in charging stations and supporting infrastructure, and the equity of the associated reduction in fuel excise,” she said.

“That’s why the Coalition is making targeted investments in charging stations and creating a national electric vehicle strategy to coordinate federal, state and local government policy.

“The Coalition is aiming for 25% + of new vehicles sold in 2030 to be EVs.”

Australia lags behind other OECD countries in setting efficiency standards to cut carbon pollution from vehicles, and government modelling shows it would deliver billions in economic benefits, including reduced fuel costs for drivers.