The Reagan administration is edging toward support of a constitutional amendment to require a balanced budget.
In recent weeks both Treasury Secretary Donald T. Regan and Council of Economic Advisers (CEA) chairman Murray Weidenbaum have spoken favorably of such an amendment. On March 18, says an administration economic official, the subject surfaced at a Cabinet meeting.
''There is general, not final, support for a positive approach to the subject ,'' said the official, who asked not to be named.
A constitutional amendment requiring a balanced US budget was reported out of the Senate Judiciary Committee last spring. With Congress recoiling from the abyss of $100 billion deficits, and with orchestrated White House backing for the proposal, proponents feel this is their year.
''I feel enormously impressed by the strength behind a balanced budget amendment move,'' says economist Milton Friedman, co-author of the amendment.
The Senate amendment would allow Congress to pass only balanced budgets. A three-fifths vote of both houses could authorize temporary budget deficits.
In addition, government income, through taxes, could grow no faster than national income. Linked together, these requirements would stop the tendency of government spending to constitute an ever-growing share of the economy, say supporters.
In a speech delivered March 11, Treasury Secretary Regan nodded approval of the amendment, saying such a move would force ''the administration and Congress to reduce federal spending and limit the growth in tax revenues.''
Six days later, before a supply-side economics conference hosted by the Atlanta Federal Reserve, CEA head Murray Weidenbaum chimed in with a circumspect endorsement.
''Frankly, I find it more difficult to argue against the urgency of this approach than I did a year ago, when I supported the interest in a constitutional amendment as primarily a form of contingency planning,'' Weidenbaum told the conference. ''To date, the federal government's ability to control its fiscal appetite is not especially awesome, and some new tools may well be required.''
The administration's high economic command is not yet marching in lockstep in support of the move, however. At the same Atlanta conference, Treasury Under Secretary for Monetary Affairs Beryl Sprinkel declined to endorse a constitutional amendment to balance the budget.
Even without a helping hand from the White House, backers of the amendment say it will soon come up for a Senate vote - ''in April, or very early May,'' predicts William Shaker, vice-president of the National Tax-Limitation Committee.
The Senate amendment has 53 co-sponsors. If passed, it would face a much more uncertain future on the other side of Capitol Hill. House Judiciary chairman Rep. Peter W. Rodino Jr. (D) of New Jersey long has indicated his distaste for a constitutional cap on federal spending. Among other things, he has labeled the amendment unenforceable, and an unwise economic straitjacket.
Judiciary would handle the bill in the House, but has no plans to do so. And committee chairman Rodino is not particularly swayed by administration words of support.
''Rodino has no plans to change his agenda, which is no agenda,'' says one congressional staffer.
There isn't much enthusiasm in the House for the amendment, says the staffer. But he admits that could change as congressmen cast desperately about for ways to reduce the political damage caused by yawning deficits.
''A growing frustration would make people change their minds. That's obviously what affected Regan and Weidenbaum. If that affects Congress, we might feel some heat'' to put it on the agenda, he says.
If the issue surfaces in the House, says the aide, it could be in conjunction with the coming vote to raise the government debt ceiling.
Sometime in May - perhaps earlier - Congress must vote to raise the current debt limit of $1.08 trillion, or some portions of the government will grind to a halt as the ability to borrow ends.
Rep. Newt Gingrich (R) of Georgia told the same Atlanta economics conference at which CEA chief Weidenbaum spoke that he would vote against the debt limit unless Congress seriously considered the amendment, left the third year of last year's personal tax cut untouched, and enacted ''dramatic'' spending cuts.
''I am perfectly willing to have the government come to a halt this spring for two, three, four weeks,'' said Congressman Gingrich. His position is rather to the right of the House mainstream.
Lobbyists behind the amendment are working on another approach to force the issue upon Congress. Thirty-one of the necessary 34 states have passed resolutions calling for a constitutional convention to consider a balanced-budget amendment.
The lobbyists hope Congress will be more scared of the uncharted territory of a constitutional convention than the possible dangers of the balanced budget amendment.
''Congress will hopefully get down to proposing'' an amendment to balance the budget before it is forced to call a convention, National Taxpayer Union president George Snyder has said.