A slightly more than three-year extension of the time for ratification of the Equal Rights Amendment was approved by the House Judiciary Committee yesterday by a 19-to-15 vote.

A move to allow states that have already ratified the amendment to rescind that ratification during the three-year extension period was rejected by a 21-to-13 vote.

An attempt to send the ratification measure back to a subcommittee to consider the question of whether a two-thirds vote is needed to pass the extension was also rejected, 19 to 15.

The bill now faces the hurdles of the House Rules Committee, where it is in some difficulty, the House floor and the Senate, where a filibuster drama against it is likely.

The size of the final vote belied the earlier atmosphere of cliff-hanging drama during a key test vote.

That key vote, which was 17 to 16, came on a compromise to shorten a seven-year extension, adopted by a Judiciary subcommittee, to three years, three months and eight days ending June 30, 1982. The compromise was made to win votes for an extension bill in the closely divided committee.

Under present law, 38 states must ratify the constitutional amendment by March 22, 1979, and only 35 have done so. Proponents say they need an extension or the amendment will fail.

The compromise almost fell apart as, just moments before the vote. Rep. Harold S. Sawyer (R-Mich.) suddenly decided he was opposed to the shortened time period.

Sawyer's vote for extension had only been won through a telephone call from former first lady Betty Ford, and he had only agreed to send the bill to the floor, not support it there, sources close to committee said.

But suddenly, as debate on the compromise three-year extension was half over, Sawyer said he was opposed to a cut in time. "If it doesn't succeed we'll have people arguing that we ought to wait for redistricting." Sawyer said, "We ought to go for the full seven years."

Judiciary Committee Chairman Peter W. Rodino Jr. (D-N.J.) quickly called for a 15-minute recess, since it appeared that the ERA proponents had lost their one-vote margin for the compromise.

Rep. Hamilton Fish Jr. (R-N.Y.,) a member of the committee, and Rep. Millicent H. Fenwick (R-N.J.), who was sitting in the audience, both interceded with Sawyer and took him to a back room, where they tried to convince him to vote for the shorter time period.

But Sawyer was adamant. "It's a delicate ego problem," Fenwick said after talking to Sawyer. "He's terribly angry. He says he's been over-lobbied."

The committee reconvened, and the vote was called. Sawyer voted no, but suddenly another opponent of the extension, Rep. James D. Santini (D-Nev.), left the room. His absence gave the ERA extension supporters the one-vote victory they needed.

The ERA would prohibit discrimination on the basis of sex. Unless extended, the deadline for its ratification is March 22, 1979.

Thirty-five states have ratified the proposal, three less than the number required. However, legislatures in four states - Nebraska, Idaho, Kentucky and Tennessee - subsequently rescinded their approval. The Justice Department has said it will be up to Congress to determine whether this is legal.

The ERA supporters have abandoned their original proposal to allow an additional seven years for state legislatures to act on the proposal, which was approved by Congress in 1972. They predicted that the panel would vote 18 to 16 to recommend the shorter extensions.

ERA backers also said they had enough votes to defeat an expected effort by Rep. Thomas F. Railsback (R-Ill.) to allow state legistures that have approved ERA to withdraw their approval during the period of the extension.

Rep. Henry J. Hyde (R-Ill.), supporting the Railsback amendment, said proponents of a simple extension "want another seven innings with only their side getting a turn at bat."

The committee room was jammed with supporters and opponents of the ERA which says: "Equality of rights under the law shall not be denied or abridged by the United States or by any state on account of sex."

Sitting in the front row were former Rep. Bella Abzug (D-N.Y.), wearing one of her familiar broad-brimmed hats, Fenwick, puffing occasionally on a pipe, and Margaret (Midge) Costanza, an aide to President Carter sporting an ERA button.

Outside, the line of people hoping to get in filled much of two corridors.

Speaking for the extension, Rep. Barbara Jordan (D-Tex.) said early ratification of the ERA is needed because the Supreme Court has refused to treat sex discrimination cases as stringently as it treats race cases.

"The Supreme Court needs help, and we can help them," she told the committee.

Opposing the extension, Rep. Sam B. Hall Jr. (D-Tex.) argued, "The rights of women are secondary, in my opinion, to the rights of the amending process of the Constitution of the United States."

Rep. Anthony C. Beilenson (D-Calif.) said ratification "is still very much a viable public issue, and I don't see any reason the public shouldn't be given additional time to consider it."

Rep. Charles E. Wiggins (R-Calif.) replied, "The debate is going on, but only among those who will not take 'no' for an answer.