In action long sought by antiabortionists, the Reagan administration has proposed that federal funds be used to finance abortions only where the woman's life is in danger -- but no longer when rape or incest are involved.

Even when a women's life is in danger, states would not have to spend public money for abortions if they choose not to, according to the administration's proposals.

The proposals, drafted by Health and Human Services Secretary Richard S. Schweiker, were included in a revised 1982 budget sent to Congress last week. Although the move would affect a relatively small number of military women and Medicaid recipients, it was seen as another signal from the administration on the abortion issue.

"It's a signal that the administration is keeping its word, that it is opposed to abortion," said David Winston, a special assistant to Schweiker. "The secretary made the decision on the basis of what is the president's position on abortion."

Winston added that Rep. Henry Hyde (R-Ill.), a leading abortion opponent, "and other anti-abortionists have never liked rape and incest included in the law, and think it is a giant loophole."

However, he said only "25 or 30" of the 6,900 federally financed abortions performed last year involved cases of rape or incest.

Both supporters and opponents of abortion yesterday predicted Congress would approve the Reagan proposal. "Both sides have agreed the funding issue is pretty much over," said Chuck Donovan, a lobbyist for the National Right to Life Committee.

Except for a brief interlude in 1980, the use of federal funds to provide abortions for Medicaid recipients has been virtually prohibited since 1977 by a series of "Hyde amendments" to HHS appropriations bills. The effect has been drastic. In fiscal 1977, the last year before abortion funding was restricted, the federal government financed 295,000 abortions. This number dropped to 2,000 in 1979, according to the Planned Parenthood Federation.

In four of the five budgets that the Carter administration submitted to Congress, it requested that federally financed abortions be allowed in cases of rape and incest. These requests, and other efforts by pro-abortionists to expand conditions for federal funds, have produced yearly bitter battles over the abortion issue.

Traditionally, the House passed amendments restricting federal funding to cases where the woman's life was in danger. The Senate liberals, including former senators Birch Bayh (D-Ind.) and George McGovern (D-S.D.), would expand the conditions. But Bayh, McGovern and other Democratic liberals the pro-abortionists depended upon were defeated last November. Their replacements oppose abortions.

This caused a reassessment among groups favoring choice on abortion. They have shifted their priorities away from the funding issue. "I don't want to say we're conceding defeat on the funding issue," said Joanne Blum, policy coordinator for the Alan Guttmacher Institute, a Planned Parenthood affiliate. "But realistically we feel we're not going to turn this Congress around on Medicaid funding."

Reagan and Schweiker are longtime abortion opponents and both have advocated a constitutional amendment to prohibit all abortions. In a March 6 news conference, Reagan also said he supports a pending piece of legislation intended to establish, without constitutional amendment, that abortion is illegal.

In addition to Schweiker, two prominent antiabortionists have won key positions in the administration. Dr. C. Everett Koop, narrator of an antiabortion film, has been named deputy assistant secretary of HHS, and Marjory Mecklenburg, president of American Citizens Concerned for Life, has been selected to head the Office of Adolescent Pregnancy Programs.