President Bush will propose a sweeping overhaul of the nation's immigration laws on Wednesday that could give legal status to millions of undocumented workers in the United States, senior administration officials said Tuesday night.

Under Mr. Bush's proposal, which effectively amounts to an amnesty program for illegal immigrants with jobs in the United States, an undocumented worker could apply for temporary worker status here for an unspecified number of years, with all the employee benefits, like minimum wage and due process, accorded to those legally employed.