The bill backed by Republican Pete Domenici, chairman of the panel, and Sen. Jeff Bingaman, its top Democrat, aims to expand access to natural gas in the area often referred to as "Lease Sale 181."

"This is the most important piece of energy legislation we have taken up since passing the energy bill last year," Domenici said in a statement, saying supplies from the area "will have a profound effect on gas supply and price."

Sen. Bill Nelson, Florida Democrat, threatened to filibuster the bill - or talk it to death - when it comes to a full Senate vote.

"It's our intent to filibuster the bill, or do whatever it takes to kill it," Nelson said.

Republicans say US consumers need the energy to head off a supply crunch, and that the area's 7.2 trillion cubic feet of natural gas could heat nearly 6 million homes for 15 years.

The panel's two Florida lawmakers, who have fought to keep the area near that state's panhandle off-limits to drilling, also voted against Domenici's plan. They favour a plan that would keep drilling at least 150 miles (241 km) off Florida's coast.

The area was shut to drilling after Florida officials complained that an oil spill or other exploration accident could foul beaches and hurt the state's multibillion-dollar tourism industry.

Sen. Mary Landrieu, a pro-drilling Democrat from Louisiana, voted against the proposal because it does not share revenues for drilling on Lease 181 - estimated at up to $11 billion over its lifetime - with coastal states hit by hurricanes Rita and Katrina.

Mississippi's two Republican senators, Trent Lott and Thad Cochran, introduced legislation on Wednesday aimed at redirecting federal dollars from 181 area drilling to states.

Under the bill, to be offered as an amendment or substitute to Domenici's, 50 percent of federal revenues from Lease 181 would go to Gulf Coast states, excluding Florida. Of those funds, the state that hosts drilling would get 65 percent and coastal counties would get 35 percent.

Up to $1.5 billion could go to Mississippi over the lifetime of the 181 leases, versus $125 million the state is expected to get from last year's energy bill.