WASHINGTON – Congressional Republicans developing an energy policy have agreed on a proposal that critics say would make it harder to require automakers to produce more fuel-efficient vehicles.

Lawmakers also reaffirmed support for an inventory of oil and gas resources in coastal waters that now are off-limits to drilling.

The Republican proposal Wednesday would bar the Transportation Department from increasing the mile-per-gallon average of automakers’ fleets – known as fuel economy – if doing so would cost industry jobs or affect vehicle safety.

Many GOP lawmakers have viewed such a requirement as common sense to avoid layoffs and a shift from larger cars. But many advocates for increased fuel economy say the government already takes such issues into account and that putting such a ban into law would hamstring the department.

“The practical effect of that is it allows auto companies to sue and delay any future fuel economy rule,” said Daniel Becker, director of energy issues at the Sierra Club.

The GOP proposal also abandoned two earlier efforts to curtail fuel use: a Senate-approved measure to stem the growth in oil use in transportation by l million barrels a day and a House-passed measure reducing gasoline demand by 5 million barrels a day.

Proposals calling for more stringent auto fuel economy have lost repeatedly in the House and Senate. Some Democrats have complained that an energy bill will not adequately address conservation without curtailing automobile fuel use.

Republicans also reached agreement on requiring an inventory of oil and natural gas reserves in all U.S. coastal waters. Environmentalists and lawmakers from many coastal states have said that could be a prelude to lifting freezes now in effect on drilling off most U.S. shores.

Continuing her fight to maintain the moratorium on drilling in the Outer Continental Shelf and Georges Bank, U.S. Sen. Olympia J. Snowe, R-Maine, joined a bipartisan group of lawmakers in urging Senate and House conferees to remove the provision requiring the inventory.

Sen. Pete Domenici, R-N.M., chairman of the energy talks, argued that such an inventory is needed to get an accurate sense of how much oil and natural gas are available. He dismissed fears that this kind of study would lead to actual exploration and drilling.

Democrats, who say they are being kept out of the energy negotiations, strongly opposed the idea.

Rep. Lois Capps, D-Calif., who is not part of the negotiating group, said the decision to include the inventory was “an outrage” because the provision was removed from energy bills that passed the House, and was not in the Senate-passed bill.

An industry advisory group, the National Petroleum Council, recommends ending the drilling freezes for gas in selected areas by 2005.

To spur oil and gas development, the Republican proposal would:

. Provide royalty payment relief for natural gas taken from very deep areas of the western and central Gulf of Mexico.

. Streamline the permitting process to allow for quicker development of natural gas in the Rocky Mountain area.

. Authorize construction of a pipeline to bring natural gas from Alaska’s North Slope to the lower 48 states, requiring that most of it go through Alaska. A decision on possible loan guarantees and tax breaks was to be made later.

Earlier, the GOP negotiators agreed to include a provision that would open a section of an Alaskan wildlife refuge to oil development. It is not certain that measure will survive because Democrats have pledged to block energy legislation that includes such drilling.