In a last-minute attempt to fashion a compromise, the House amended an industry-backed version of the Alaska lands bill yesterday to make it more palatable to environmentalists.

However, Rep. Morris Udall (D-Ariz.), sponsor of a rival conservationist-supported measure, said his opponents "haven't even come close to making their bill acceptable. They're trying to pick up some undecideds, but I think we're still ahead."

It was a day of heated debate in the House chamber.Rep. John Dingell of Michigan shouted angrily at fellow Democrat John Seiberling of Ohio. Two Republicans, John Anderson of Illinois and Don Young of Alaska, railed furiously at one another.

If the issue was confusing from a partisan viewpoint it was equally-confounding on substantive level. Each side claimed the other would hamper oil development and wipe out herds of caribou.

Two bills are competing to determine the fate of more than a hundre million acres of Alaskan wilderness: the industry-backed measure sponsored by Dingell and Rep. John Breaux (D-La.) and the Udall-Anderson bill, supported by environmentalists and the administration.

In a letter ot House members yesterday, President Carter termed it the "conservation vote of the century." He said the Breaux-Dingell bill is "unacceptable" because it would allow oil exploration in the Arctic National Wildlife Range, a caribou claving area. Each side claimed the other would chop in half two major wildernesses, Admiralty Island and Misty Fjords in southeast Alaska.

Yesterday on a motion by Rep. David Emery (R-Maine), the House amended the Breaux-Dingell bill to postpone exploration in the Arctic range until the National Petroleum Reserve in northwestern Alaska is thoroughly explored.

Another amendment to the Breaux-Dingell version, sponsored by Rep. Keith Sebelius (R-Kan.), would increase Gates of the Arctic National Park by more than 3 million acres and the Wrangell-St. Elias Park Preserve by more than 2 million acres. The effect would be to reduce sport hunting in Gates of the Arctic and reduce mining in Wrangell-St. Elias.

Hunting has been a major issue in the debate, with the National Rifle Association vigorously backing the Breaux-Dingell bill. However, Sebelius got the House to narrow the differences so that while Udall would ban hunting on 91 million acres, Breaux-Dingell would now forbid it on 92 million.

A third amendment adopted yesterday was Louisiana Democrat Jerry Huckaby's proposal to reclassify 7 million acres in Noatak and Bering Land Bridge wildlife refuges into park preserves, a category that would forbid mining but allow sport hunting.

The three amendments represent major concessions by proponents of the Beaux-Dingell bill, but they apparently did little to soften opposition by environmentalists.

"We have not cured the bill's basic defects," Anderson told the House. "There are no more Alaskas. This is the last opportunity this body will have to deal with this issue in a proper way."

Alaskan Young, however, called Anderson's position "unconstitutional morally wrong and not the Republican position." He charged that the Udall-Anderson bill would steal 14 million acres of land claimed by the state.

A final vote is expected today on the two bills, both of which would roughly double the size of the nation's parks and national wildlife refuges, adding an area of spectacular natural beauty larger than the state of California.

The House has yet to decide what areas should be open to oil exploration, hard-rock mining and timber cutting-issues which will determine whether Carter vetoes the final bill and instead seeks to protect the areas by administrative decree.