California, which has become a leader on environmental issues in the United States, passed a state law in 2005 that would require new vehicles to meet progressively tighter standards for greenhouse gas emissions starting with 2009 models.

But the state needs a waiver from the federal government to implement the law and says it has run out of patience awaiting it. Schwarzenegger set an Oct. 22 deadline six months ago for a decision and threatened to sue if the EPA failed to act by then.

"It is almost two years since we asked for this waiver. The governor feels we have been patient enough. He has met with the EPA administrator and with the president on this and has sent letters to them both. We have done everything we can and now it is time for action," McLear said.

The EPA said earlier this month it expected to make a decision on California's request by the end of 2007.

Schwarzenegger, a Republican, has said repeatedly that the US government is moving too slowly on climate change issues and that states like California must lead the way.

US automakers are fighting California's plans in the courts. In a separate case, a US federal judge last month threw out a California lawsuit that had sought for the first time to hold vehicle manufacturers responsible for damages caused by climate-changing greenhouse gases.