In July last year, the government announced a plan for 18 electric vehicle charging stations along the Bruce Highway from Cairns to Coolangatta and west to Toowoomba, at a cost of $3 million to install, including 12 months' free charging.

When fees were introduced, it was expected the cost to charge an average car would be about $45 per month.

Deputy Premier Jackie Trad said the extra funding would mean a more seamless, reliable journey for electric car owners.

The exact location and number of the new chargers is yet to be announced.

Main Roads Minister Mark Bailey said the extra charges would bolster the 17 already installed.

"These additional chargers will give drivers more options and reduce 'range anxiety'," he said.

"It will also provide more opportunities for people to take a break and survive the drive."

Mr Bailey said electric vehicles' benefits included eliminating exhaust emissions, improving air quality and helping to address climate change.

As of early 2018, there were 1300 electric cars, including hybrid cars, registered in Queensland.

The Palaszczuk government has a goal of 50 per cent renewable energy by 2030.

Ms Trad will hand down her first state budget on Tuesday.