President Reagan has decided to launch a "full-court press" designed to win Republican support for a tax-revision bill in the House next week, despite GOP objections to the legislation approved by the Democratic-controlled Ways and Means Committee, officials said yesterday.

The president plans to urge Republicans to vote for the Ways and Means legislation if their alternative is rejected, officials said. Reagan intends to emphasize the importance of getting a bill through the House so the Senate can take up the issue next year, they added. Reagan earlier this week issued a carefully worded statement urging Congress to take action on tax legislation, saying both the Ways and Means bill and the House Republican alternative had positive aspects, but not choosing between them.

Democratic leaders said he would have to get more involved to ensure that a tax bill is passed by the House this year.

According to a senior administration official, Reagan decided yesterday, after a meeting of the White House legislative strategy group and discussions with aides, to step up lobbying on the tax issue.

The president will kick off this effort today with an appeal for action in his regular Saturday radio address.

Ways and Means Chairman Dan Rostenkowski (D-Ill.) is scheduled to give his party's response to the president's radio speech. Rostenkowski has been pushing the administration for a presidential endorsement of his committee's bill, which he has said is the only one that has a chance of winning House approval.

The lobbying effort by the administration will continue on Sunday with a television appearance by Treasury Secretary James A. Baker III, a White House official said. On Monday, Reagan is planning to send a letter to House members. A vote is expected at midweek.

Reagan is also planning to make telephone calls and, if necessary, conduct one-on-one meetings with some House members at the White House.

The official said Reagan's effort is designed to build enough support among Republicans for a tax bill to guarantee passage in the Democratic-controlled House next week. Leaders in both parties have predicted the vote would be close, and Rostenkowski has been rounding up Democratic votes for it.

Reagan "will do things in a way that enhances the vote total rather than reduces it," said the official. "Now is the time to speak to it."

Before Thanksgiving, Reagan approved, then withdrew, an endorsement of the committee bill because aides said he wanted to hear the concerns of GOP members and give them a chance to prepare an alternative. The Republican lawmakers met with the president Tuesday.

Now "there will be no doubt of Reagan's absolute and total commitment to getting a bill passed," said the official, who spoke on condition he not be identified.

While Democrats have said that Reagan needs to get 75 Republicans to support the measure, White House strategists said they believe the total is less than that, perhaps 35 or 40.

The official said Reagan did not want to alienate House Republicans who are offering an alternative to the Ways and Means bill. But, he said, Reagan realized that a concerted effort is needed to get some legislation through the House before Congress adjourns for the year.

The tax bills are expected to be considered under a rule that would allow a vote on each version, but not on individual items. Members of both parties have said failure to get a bill through the House next week could doom Reagan's top domestic initiative of the year.