President Reagan yesterday called the right to vote the "crown jewel of American liberties," and said he favors a 10-year extension of the 1965 Voting Rights Act. But he said in the same statement that he also would support a different version if it contained two weakening provisions that critics claim would leave the act unenforceable.

The president's two-sided statement reflected a split within the administration that reportedly had presidential counselor Edwin Meese III, White House chief of staff James A. Baker III and others on one side supporting the House-passed version that Reagan had earlier called "pretty extreme," and Attorney General William French Smith leading on the other side urging the weakening.

Housing and Urban Development Secretary Samuel R. Pierce Jr., the only black in the Cabinet, reportedly sided in part with Smith during Wednesday's Cabinet discussion of the issue.

One administration source said yesterday's statement was deliberately fuzzed to provide political maneuvering room and keep both sides happy.

"It was intended to be flexible," he said.

Reagan said in the statement that he would accept a "direct extension" of the existing law that expires in August, but would also accept a "modified version" of the somewhat different bill just passed by the House.

He did not say what he meant by modified, nor would aides later. But he did say he was in favor of a "reasonable" bailout provision under which states could free themselves from the requirements of the act by several years of good conduct. The House bill has a bailout provision. Reagan indicated without specifying that he would prefer a different one.

He also said he favors a provision under which, to prove a violation of the act, the government would have to show not only that minority group members were excluded from public office or denied the right to vote because of local election laws, but also that officials responsible for the local laws intended the discrimination. He said such a provision is already in law.

But the House bill specifically renounces such an intent test, which civil rights groups say would cripple enforcement.

The president also said he would go along with a House provision he had criticized earlier requiring bilingual ballots in areas, like Texas, where there are many persons who do not speak English.

The voting rights issue has plainly divided the administration, on political as well as substantive grounds.

As recently as yesterday morning, members of Congress were getting calls from the White House with the news that Reagan had decided to go along with the House-passed version of the bill, which passed overwhelmingly.

Though conservatives want the act changed, members were told Reagan did not feel he could afford a bloody battle on this civil rights issue at the same time he was trying to push through painful budget cuts.

Reporters were called to the White House yesterday afternoon for a briefing at which Attorney General Smith was to announce the new White House plan.

But Smith never appeared for the briefing, and two hours later the White House merely released a seven-paragraph written statement, refusing to answer questions or provide clarification.

One administration source said that plan to go along with the House bill had been made by high-level presidential advisers, including Meese and Baker, without consulting the attorney general. The White House would not confirm that.

The source said that Smith, who has pushed for a simplified bailout and an intent standard, was furious when he found out yesterday morning what had happened and charged off to the White House for a face-to-face meeting with the president where he demanded that it be changed.

"A lot of people in the White House were convinced that politically the best thing to do is cave-in . . . but the president agreed with the attorney general that he would not go along with the House bill," the source said.

The issue already has played a role in some congressional and local election contests. Rep. Wayne Dowdy (D-Miss.), who supported extension while his Republican opponent opposed it, won a special election earlier this year, returning to Democratic control a congressional seat previously held by Republicans.

Virginia Attorney General J. Marshall Coleman, who opposed extension, lost the race for governor of Virginia Tuesday to Democratic candidate Charles S. Robb, the state's lieutenant governor.

In addition, Ralph Neas of the Leadership Conference on Civil Rights said earlier this week that the civil rights community is planning to mobilize on the issue in the 1982 congressional elections.

Lawyers who specialize in the voting rights area complain that it is virtually impossible to prove intent in many cases, especially those where the persons who wrote the laws may have been dead for many years.

Laura Murphy of the American Civil Liberties Union, said, "We feel it's an outrage for the president to support an intent test. You would basically have to have people come out of their graves and confess that they had a racist motivation to show intent. I don't understand why the Republican Party would actually send this message to black people when the unemployment rate is going up."

Sen. Edward M. Kennedy, (D-Mass.), a strong supporter of the voting rights extension, said that any expansion of the bailout provisions beyond what had already been approved by the House would amount to "a back-door repeal of the most critical safeguards in the act."

The debate over voting rights was also an emotional issue for blacks inside the Reagan administration.

Two black White House aides, Mel Bradley and Steve Rhodes, asked for and were given the opportunity to speak to the Cabinet Wednesday on behalf of the House-passed version. Bradley had accompanied former senator Edward M. Brooke to a meeting with the president the day before where both had lobbied for the House bill.

At the Cabinet meeting, following Bradley's presentation, Pierce went along with Smith in saying that the bailout provisions in the House bill were too tough, but he would not go along with an intent standard.

Pierce reportedly suggested to Reagan that he not endorse any specific legislation but issue instead a statement favoring a strong voting rights bill with "reasonable" bailout provisions.

Health and Human Services Secretary Richard S. Schweiker and Trade Representative Bill Brock spoke in strong support of Bradley, saying they also favored the House bill. Energy Secretary James B. Edwards and White House aide Lyn Nofziger agreed with Smith.

Later, civil rights groups expressed anger over Pierce's comments. He had not consulted them before the meeting nor had he talked with Bradley, and all had assumed he would remain silent during the Cabinet discussion. Pierce, upon learning that civil rights lobbyists were saying he had undercut Bradley, heatedly denied that he had.