House Democrats dangled the bait of a balanced 1982 budget before Congress yesterday in a daring, desperate effort to outbid President Reagan for the support of conservatives in next week's House vote on the budget.

The plan, reported to be under "serious consideration" by some party leaders as a new way to blunt Reagan's economic offensive in Congress, would defer any tax cut for individuals until 1983 and use the resulting revenues to erase most or all of the $25.6 billion deficit anticipated in the Democrats' budget alternative.

The plan is based on an assumption that people want a balanced budget more than they want an across-the-board tax cut, which used to be Republican orthodoxy but isn't any more. Now it should be "the kind of policy that will restore people's faith and confidence in Democratic wisdom and leadership," said deputy Democratic whip Bill Alexander (D-Ark.), who proposed the idea.

Speaker Thomas P. O'Neill Jr. (D-Mass.), insisting he didn't mean to abandon hope for the Democrats' budget alternative in comments to reporters Monday, appeared cool to the balanced-budget initiative. But Alexander asked the Rules Committee to permit a vote on the proposal, and Budget Committee Chairman James R. Jones (D-Okla.) said he was seriously considering including it in an omnibus amendment that he will propose on the House floor.

The House Democrats' attempt to capitalize on strong congressional yearnings for an end to budget deficits came as Senate Republicans finally closed ranks behind a budget resolution that itself was modified under pressure from GOP conservatives to increase chances of a balanced budget by 1984.

With the Republican revolt quelled, the Senate Budget Committee voted 15 to 6 to approve a $699.1 billion spending blueprint for fiscal 1982, including a $48.8 billion deficit, that was drafted to accommodate Reagan's overall economic program.

It is basically the same package that was rejected by the committee earlier this month, except for theoretical economies that have the effect of reducing projected spending levels and deficits by $5.1 billion in 1982, $31.5 billion in 1983 and $44.7 billion in 1984.

Sen. William L. Armstrong (R-Colo.), leader of the earlier revolt, hailed the new version of the budget as one that gives the country a "fighting chance to achieve a balanced budget by 1984," while Sen. Ernest F. Hollings (D-S.C.) said it was based on "phony" figures and Sen. Gary Hart (D-Colo.) said it relied on "dubious accounting to cover up $40 billion to $50 billion worth of deficits" for the future.

In the 15-to-6 vote, all Republicans supported the budget, including Armstrong and two other Republicans, Sens. Charles E. Grassley of Iowa and Steven D. Symms of Idaho, who teamed up with the Democrats to defeat the earlier version by a vote of 12 to 8. Three Democrats -- J. Bennett Johnston of Louisiana, Lawton Chiles of Florida and Jim Sasser of Tennessee -- also voted for the budget this time.

In the House, the Democrats gave themselves one more day to try to come up with sweeteners for their budget alternative, which probably will include some increases in defense spending over what was recommended by the House Budget Committee. They also postponed House action on the budget until next week.

As it now stands, the Democrats' $714.5 budget proposal shifts some money from defense to social programs and anticipates less of a tax cut than Reagan recommended, resulting in a lower deficit. But the Republicans, joined by some conservative Democrats, have countered with a revised $689 billion Reagan budget, including a deficit lower than Reagan's.

Reagan has projected a $45 billion deficit, and his House supporters would trim it back to $38.9 billion. The Democratic alternative anticipates a deficit of $25.6 billion.

The issue is expected to be decided by conservative Democrats. Minority Leader Robert Michel (R-Ill.) claimed yesterday that 26 of 44 members of the Democrats' conservative caucus will vote for the revised Reagan budget, with 13 more "wavering." If there are no Republican defections, 27 Democratic switches could carry the day for Reagan. Michel said he would be surprised if there were more than 3 Republican defections.