Attorney General William P. Barr said a bill that would forbid states to impose restrictions on most abortions goes far beyond the standard set in Roe v. Wade and he questioned Congress's authority to enact such a change.

Barr's attack on the Freedom of Choice Act in a letter released yesterday reflects the increased attention to the bill this year from both foes and supporters. President Bush, who has repeatedly promised to veto any measure that expands access to abortion, yesterday told a religious group in Chicago that the bill "is not right" and "will not become law as long as I am president."

Abortion-rights groups and legislators are increasingly turning to the Freedom of Choice Act because the Supreme Court is widely expected to soon cut back or overturn the constitutional protections for abortions in the 1973 Roe v. Wade case.

House Speaker Thomas S. Foley (D-Wash.) has predicted that if Roe is overturned, Congress will pass the abortion-rights bill this session, after avoiding it for the past two years. But Senate Majority Leader George J. Mitchell (D-Maine), a supporter of abortion rights, has expressed reservations about the bill, suggesting a constitutional amendment as a better route.

The bill, which has 131 co-sponsors in the House and 31 in the Senate, prohibits states from restricting the right of a woman to terminate a pregnancy before the fetus is viable or "at any time necessary to protect the life or health of the woman."

In a letter to Rep. Henry J. Hyde (R-Ill.), a staunch opponent of abortion, Barr said, "This legislation would impose on all 50 states an unprecedented regime of abortion on demand going well beyond the requirements of Roe v. Wade."

The exact scope of the bill is a matter of debate. Both Barr and the American Civil Liberties Union, which opposes abortion restrictions, agree that the Freedom of Choice Act would probably prohibit state laws requiring parental notification or consent before minors obtain abortions. A number of states have adopted such restrictions.

In addition, Barr said that while Roe allows states to protect fetuses after the second trimester, the Freedom of Choice Act appears to prevent states from regulating abortions even after the fetus becomes viable. It "probably" would prohibit states from banning abortions "for reasons of sex-selection or birth control," Barr wrote.

The Congressional Research Service in 1990 characterized the bill more narrowly, suggesting it could easily be interpreted as status-quo legislation.

Kate Michelman, president of the National Abortion Rights Action League, said yesterday that Bush's vow to veto the bill "demonstrates that this president is much more interested in kowtowing to the anti-choice minority than in safeguarding the health and lives of American women."