SACRAMENTO — A landmark law that has been a symbol of California’s tough environmental philosophy for more than 40 years is facing an unlikely challenge from Democrats, including Gov. Jerry Brown, who contend that regulations protecting the environment have been abused and are thwarting legitimate development.

With the Legislature moving toward adjournment this week, prospects of weakening the law, known as the California Environmental Quality Act, seem stronger than in recent memory, lawmakers said. Mr. Brown called rewriting the law “the Lord’s work,” and the effort has won widespread support from newspaper editorial boards.

Senator Darrell Steinberg, the Democratic leader, said Tuesday that he was confident that his proposed changes to the law would win legislative approval this week and be sent to Mr. Brown.

That said, the changes Mr. Steinberg is championing — which include exempting urban projects from parking and aesthetic reviews, and speeding up the pace of litigation — are considerably short of the broader rollback of environmental reviews sought by business leaders.