Chances for passage of the Equal Rights Amendment grew more remote yesterday as the Oklahoma Senate voted against ratification. But a state senator kept the issue barely alive by introducing a motion to reconsider.

The National Organization for Women had waged an intense lobbying campaign in Oklahoma in the last month, with a heavy schedule of television advertising and visits in the past several days from well-known Americans including former vice president Walter Mondale, former House speaker Carl Albert and actor Alan Alda.

The vote on the amendment, which would ban discrimination based on sex, was 27 to 21 against ratification.

With just over five months remaining before the June 20 ERA ratification deadline, legislatures in several states are rushing to take up consideration.

ERA supporters are also concentrating on Illinois, where the vote is thought to be close. There they hope to overturn a procedural rule that required ERA approval by a three-fifths vote. But Senate Democrats caucused for several hours yesterday before recessing when they realized they did not yet have a majority for the rule change.

In Georgia, a House committee voted, 6 to 3, this week to send the ERA to the House floor with a favorable recommendation. The bill, which was soundly defeated by the Georgia General Assembly in 1974 and 1980, is expected to come up for vote Monday. Its chances are not considered good.

Meanwhile, in Florida, NOW is waging an intensive ad campaign to persuade state legislators to support the ERA. A vote has not been scheduled, but the legislature is to adjourn for the year in mid-March.

The ERA has been approved by 35 of the 38 states required to make it part of the Constitution.

But chances for ratification were dealt a serious blow Dec. 23 when U.S. District Court Judge Marion Callister issued an opinion in Boise, Idaho, that Congress violated the Constitution when it voted in 1978 to extend the deadline for three years. He also ruled states can rescind their ratification votes.

Five states have attempted to rescind, but Callister, a Mormon, did not spell out what constitutes a valid rescission.

His opinion has been appealed to the Supreme Court by NOW and the Justice Department is expected to deliver its appeal to the court today. The Supreme Court is to decide tomorrow whether to provide an expedited review of the case.

In Illinois yesterday, state legislators convened at noon to hear Gov. James R. Thompson's State of the State message. They were scheduled to leave the Capitol at the end of the day and were not due to return until Thompson's budget presentation in early March.

In his State of the State speech, Republican Thompson, an ERA supporter, once again called for ratification of the amendment. And he criticized lawmakers for failing to do so in past attempts.

Although the ERA has been approved by the Illinois House and Senate, it has not been endorsed by both in the same session.

At issue in the pending procedural fight is the rule requiring a three-fifths majority to approve amendments to the U.S. Constitution. ERA supporters want the rule changed so a simple majority, 30-29 in the Senate, would be sufficient.

The Senate defeated such a move in 1979. A proposal to change the three-fifths rule in the House failed last year.

A vote on the ERA itself is unlikely until later in the year.