A coalition of environmental groups is targeting about 30 members of the House and a handful of senators in a final push to win swing votes to defeat proposed drilling in Alaska’s Arctic National Wildlife Refuge.

In a vigorous lobbying campaign, the environmentalists are trying to rally opposition in the districts of lawmakers whose votes they say are uncertain. As proposed drilling moves closer to becoming law, the environmentalists are scrambling to find enough votes to derail legislation that has seemed headed for passage. Supporters maintain they will have the votes to open the refuge.

“The stakes are as high as they’ve ever been,” said Melinda Pierce, a lobbyist in the Washington office of the environmental group Sierra Club. “It is a top priority of the environmental community. It is really sort of an iconic vote.”

Environmentalists recently walked door-to-door in the Minnesota district of Rep. Mark Kennedy (R), providing a cell phone for constituents to call their representative and ask him to vote against drilling. In the New York district of Rep. Sue W. Kelly (R), they ran phone banks urging constituents to call and write letters to their lawmaker. In Washington state, they’re running advertisements on seven buses telling people to call Rep. David G. Reichert (R) and seek protection of the refuge.

The legislation to open the refuge to drilling is expected to be included in budget measures that soon will go before the full House and Senate. By including the measure in the budget reconciliation, which cannot be filibustered, supporters of drilling hope to overcome tactics used in the past by opponents to kill drilling legislation.

In legislative action yesterday, the Senate Budget Committee approved a bill that calls for drilling, the final step before the measure goes to the full Senate. The House Resources Committee approved a similar measure yesterday that must now be approved by the House Budget Committee before going to the floor.

Since the fate of drilling is tied to passage of the budget, the proposal to open the refuge could fail because of unrelated controversies over other elements of the budget, including trade policies and cuts in food stamps.

In 1995, lawmakers approved drilling in the refuge, but President Clinton vetoed the legislation. This time around, President Bush has made drilling a high priority and has pressed Congress to send him the legislation.

Majorities in both chambers have signaled support for drilling in the refuge. In April, Congress approved a budget blueprint that anticipated revenue generated by the drilling.

Environmentalists are asking opponents to vote against the budget when it reaches the full House and Senate as a way to kill drilling. They say they have targeted lawmakers for lobbying who have previously voted against drilling in stand-alone legislation but who have not committed to voting against the budget.

Drilling in the refuge has been debated in Congress for decades. The issue pits preservationists who say the refuge and its wildlife would be despoiled by drilling against oil companies and other business interests who argue that development is needed to produce more domestic energy and create jobs.

Supporters of drilling also have been lobbying members of Congress, though they do not appear to be pressing as hard as environmentalists.

The American Petroleum Institute, an industry trade group in Washington, has been seeking drilling in the refuge but has not made it the top priority.

“We haven’t dropped everything to focus on this,” said the institute’s president, Red Cavaney. But he added: “We take it seriously. We’re trying to do all we can.”

Several oil companies said that they support opening the refuge to drilling but that they are not lobbying on the issue. Others, including Chevron Corp., declined to say whether they are lobbying. A spokesman for Exxon Mobil Corp., the world’s largest publicly traded oil company, said its lobbying on the refuge is done through a group called Arctic Power, of which the company is a member. Arctic Power says it has arranged for native Alaskans who support drilling to meet with more than 100 lawmakers on the issue.

Teresa Wong, a spokeswoman for Anadarko Petroleum Corp. of Houston, said that when lawmakers ask, the company gives them information explaining their support for drilling but that lawmakers’ positions have long been staked out. “Because it’s such a divisive issue, a lot of minds already are made up,” Wong said.

Some unions said their lobbyists are pressing lawmakers to approve drilling as a way to generate jobs. Galen Munroe, a spokesman for the International Brotherhood of Teamsters, said opening the refuge is a “key issue” for the union and that it has several lobbyists focusing on swaying Democrats and pro-labor Republicans. In some cases, local union leaders are calling their lawmakers’ offices to make the case.

Environmentalists are focusing heavy efforts in New Jersey, where they hope to win the votes of several moderate Republicans. They are running print and television ads in the state, among other efforts.

Pro-drilling groups declined to name the lawmakers they are lobbying or describe their tactics in detail.

Spokesmen for several lawmakers targeted by environmentalists said they had not been lobbied by pro-drilling groups but that they had received phone calls and letters from a number of constituents opposing drilling.

The impact of environmentalists’ lobbying is uncertain. Some of the lawmakers whose votes they are seeking continue to oppose drilling but will not decide how they will vote on the budget until they see the final version of the legislation, spokesmen said.

“The congressman at this time thinks it’s premature to say how he would vote,” said Jason Galanes, a spokesman for Rep. Frank LoBiondo (R-N.J.).