General Motors has it will no longer back the outgoing Trump administration's effort to stop California from setting its own emissions rules in an ongoing court fight.

According to Reuters, GM chief executive Mary Barra said in a letter to environmental groups it was "immediately withdrawing from the preemption litigation and inviting other automakers to join us".

The news agency said the reversal came came as GM sought to work with president elect Joe Biden who has made boosting electric vehicles (EVs) a top priority. The Detroit automaker has laid out an ambitious strategy to boost EV sales and last week said it would increase spending on EVs and autonomous vehicles by 35% from previously disclosed plans.

Barra reportedly said she believes "the ambitious electrification goals of the president-elect, California, and General Motors are aligned, to address climate change by drastically reducing automobile emissions".

The White House and Justice Department declined to comment to Reuters. Environmental Protection Agency spokesman James Hewitt said "it's always interesting to see the changing positions of US corporations".

Reuters noted, in October 2019, GM joined Toyota Motor, Fiat Chrysler Automobiles and other automakers in backing the Trump administration in its bid to bar California from setting its own fuel efficiency rules or zero emission requirements for vehicles.

California and 22 other states and environmental groups challenged the Trump administration's determination federal law bars California from setting stiff tailpipe emission standards and zero emission vehicle mandates.

Barra was among corporate and labour leaders who met virtually last week with Biden, Reuters noted.

Barra this week said she was "confident that the Biden administration, California, and the US auto industry, which supports 10.3m jobs, can collaboratively find the pathway that will deliver an all-electric future".

Biden said in a statement: "GM's decision reinforces how shortsighted the Trump administration's efforts to erode American ingenuity and America's defences against the climate threat truly are."

Reuters noted the Trump administration in March finalised a rollback of fuel efficiency standards to require 1.5% annual increases in efficiency through 2026, well below the 5% yearly boosts in Obama administration rules it discarded.

California is the largest US auto market, accounting for about 11% of all US vehicle sales, and many states choose to adopt its green vehicle mandates, Reuters added.