LOS ANGELES — Top Democratic lawmakers in California are moving to enact sweeping legislation to protect undocumented immigrants from deportation, the first sign of what they say will be an effort to resist immigration policies championed by President-elect Donald J. Trump.

The measures, which will be introduced Monday, would provide free legal help to undocumented immigrants during deportation proceedings, offer more assistance in criminal court, and further limit local law enforcement’s cooperation with federal immigration agents. The measures contrast sharply with the kind of policies that Mr. Trump pressed on the campaign trail.

“Throughout the presidential campaign and since, the president-elect has made many troubling statements that run counter to the principles that define California today,” said Kevin de León, the Senate president pro tempore, who is backing the package. “There is no greater policy area than immigration where the comments run headlong to the values we share as Californians.”

The legislation suggests the level of opposition Mr. Trump may face in California, a state where 40 percent of the population is Latino. The leaders of both chambers of the Legislature are Latino, as is the state’s attorney general-designee, Xavier Becerra. Mr. de León said that pushing immigration measures would be a priority of the Legislature.