The roadless rule has been subject to intense debate since President Bill Clinton signed the legislation just days before leaving office.

Similar legislation has attracted broad support in the Republican-led House, with more than 170 lawmakers, including several Republicans, backing the plan.

"Today, with this rule under legal challenge, I believe that it is important to take another step forward with ensuring that this rule is codified so that it has the full force of law," said Sen. John Warner, a Virginia Republican who co-sponsored the bill with six other lawmakers.

The legislation would prohibit the construction of roads unless necessary to protect the public from forest fires or other natural disasters. Roads could also be built to provide "essential" access to the public and to remove minerals from public land under old leases that have not expired.

Environmental groups argue the rule is vital to protecting pristine forest land from timber, mining and oil companies, which cannot access the land without building roads.

The USDA has received more than two million letters, faxes and postcards supporting the rule, the most ever for a federal environmental measure.

"The public overwhelmingly supports protecting national forests," said said Tiernan Sittenfeld, spokeswoman for the U.S. Public Interest Research Group.

"It's clear that many members of Congress are representing the well-wishes of their constituents, and we urge the Bush administration to do the same," she said.

The Bush administration has said it would adopt the roadless plan, but modify it to include more local input so changes to the forest are made on a case-by-case basis.

Last year, a federal judge in Boise, Idaho, blocked the Bush administration from carrying out the rule, calling the administration's proposal to modify it a "Band Aid approach."

The case is now before a federal appeals court in San Francisco.