Like the mythical rock of Sisyphus, an effort to amend the nation's pesticide law has begun its annual roll up Capitol Hill.

But despite the pleadings of environmentalists and consumer groups -- and the Environmental Protection Agency's tacit agreement that the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) needs revising -- the chances of topping the crest appear no better this year than they have for the last three.

Rep. Berkley W. Bedell (D-Iowa), whose House Agriculture subcommittee has held three days of hearings on FIFRA, vowed this week to have a bill out of his panel this summer. But there is no action on the Senate side and, according to aides on the Senate Agriculture Committee, there isn't likely to be.

"I personally don't think you'll see much happening on FIFRA here, because we don't have time to do it," said a Democratic committee aide. The Senate is looking at a simple extension of FIFRA, the same solution that has let Congress avoid the thorny issues of pesticide regulation for the last three years.

But environmental groups, with increasing support from public-health organizations and organized labor, contend that revisions can't wait another year.

A coalition of 40 groups, from the American Public Health Association to the American Federation of Teachers, has thrown its support behind a bill introduced by Rep. George E. Brown (D-Calif.) that would force additional safety testing, speed up cancellation of dangerous chemicals and put more information on pesticide hazards in the hands of local communities.

FIFRA is an "anachronistic statute" that is "riddled with loopholes and industry-oriented provisions," Nancy Drabble, director of Public Citizen's Congress Watch, told Bedell's panel. "Most Americans probably assume that all pesticides have been carefully examined by EPA and have passed rigorous health and safety tests. This is simply not true."

EPA officials do not deny that the agency is behind on its work in pesticides. Thirteen years after Congress ordered the agency to review the safety of hundreds of pesticides already on the market, the EPA has completed safety tests on only six out of 600 chemicals that provide the active ingredients in more than 40,000 pesticides.

In testimony before the subcommittee last month, EPA pesticides chief John A. Moore acknowledged that the agency would like to see some changes in the law. "You can only go so far to make a silk purse out of a sow's ear," he said.

The EPA's suggestions for FIFRA were overruled by the Office of Management and Budget, however, and efforts by Bedell and Rep. Pat Roberts (R-Kan.) to draft a bill based on Moore's testimony already have drawn fire from industry.

But some industry lobbyists are nervous about the continued stalemate, which has created restiveness in the House and prompted challenges to the Agriculture Committee's iron-fisted control over pesticides.

Rep. Henry A. Waxman (D-Calif.), for example, is seeking to overhaul the pesticide tolerance system through the Food, Drug and Cosmetic Act, over which his Energy and Commerce subcommittee on health and the environment has jurisdiction.

Industry interests have the support of the Reagan administration in most of those side battles, but environmental lobbyists say they are not without their own ace in the hole.

Chemical manufacturers are keenly interested in winning passage of a patent extension bill, similar to one already approved for pharmaceutical companies. The pesticide patent bill turned into a embarrassment last year for its House sponsor, Rep. Dan Glickman (D-Kan.), when it was disclosed that the measure, drafted by the National Agricultural Chemicals Association, also would overturn a Supreme Court ruling on public disclosure of health and safety data.

Glickman has declined to reintroduce the bill this year, and its Senate sponsor, Sen. Charles McC. Mathias Jr. (R-Md.), says it isn't going anywhere until some progress is reported on FIFRA.

"I think it'll just sit there," said Jack D. Early, president of the National Agricultural Chemicals Association. "I'm being held hostage in that arena, but that's the way things work in this town."