Israel took a step today toward changing the status of the occupied West Bank of the Jordan River and the Gaza Strip, extending to the more than 1 million Arabs in the areas some of the same administrative regulations in effect in Israel.

The move by the Cabinet of Prime Minister Menahem Begin was promptly criticized by some here as an effort to tighten Israel's grip on the areas captured in the 1967 Middle East war and possibly a move toward annexation.

"A strong odor of annexation emanates from this Cabinet decision," said a spokesman for the opposition Labor Party, which ruled Israel until it was defeated three months ago by a coalition headed by Begins.

Cabinet Secretary Arye Naor said, however, that "this is not annexation. You cannot annex the land of Israel for the people of Israel because it already belongs to them."

Announcement of the move, decided in today's weekly Cabinet meeting, came only three days after U.S. Secretary of State Cyrus Vance ended a largely inconclusive peace mission to the Middle East. During Vance's visit to Israel, the Israeli government gave no public indication it was contemplating today's move.

Vance reported to President Carter at the White House Sunday on the results of his talks with Middle East leaders. A White House statement issued afterward said that during Vance's trip "progress was made in some areas," but it added that "major differences between Arabs and Israelis remain" in the areas of a Palestinian role in negotiations and the nature of secure borders.

[Carter and Vance will meet with the foreign ministers of Israel, Egypt, Lebanon, Syria, Jordan and Saudi Arabia in the United States next month to continue the disscussions, the White House said.]

The Israeli decision came less than two months after the inauguration of Begin and contrasted with the care taken by previous administrations not to change the legal status of the territories captured 10 years ago.

It followed a decision earlier this month to grant the status of permanent settlements to three Jewish work camps on the West Bank, which aroused protests from Carter and Vance.

Naor said today's action did not change the legal status of the residents of the territories or impose Israeli law. He said it maintained the legal framework that existed before the 1967 conquest.

Begin's Likud Party and other parties in his coalition government have said they believe Israel can go even further and impose Israeli law on the occupied territories - in effect, annexing them - but only with the agreement of the Israeli Parliament. Today's decision did not need parliamentary approval, Naor said.

Army sources said the military government that administers the West Bank and the Gaza Strip has a number of plans ready for raising the standard of life in the occupied territories.

Begin told Cabinet members that inhabitants of the territories can no longer be discriminated against, Naor said.

Naor gave two examples of changes under the new status:

Labor practices will come in line with Israeli policies, including an end to child labor.

Health services, including funding and building of hospitals and other facilities, will be brought up to Israeli standards.

Naor said a committee of ministers will work out the details, but he would not say when the changes would go into effect.

"The new government has proven that it acts quickly," he said.

Israeli troops captured the Gaza Strip from Egypt and the West Bank of the Jordan River from Jordan during the six-day 1967 Middle East War.

Naor said the move would not affect the Golan Heights of Syria, one of the two other regions captured in the war. He made no mention of the other occupied region, the Sinai Desert of Egypt.