The Carter administration, seeking to head off a new round of price increases scheduled for next week, took the unusual step yesterday of asking businesses to defer part of them until next summer.

Officials of the Council on Wage and Price Stability said they acted after learning that many firms are planning sizable price increases effective Tuesday, apparently out of fear that the government will soon impose wage-price controls.

Some policymakers contend these "anticipatory" price increases have unnecessarily driven up the consumer price index, which has been rising at an 18.2 percent annual rate this year. President Carter repeatedly has rejected wage-price controls.

Meanwhile, Treasury Secretary G. William Miller, trying to calm the financial markets, said the government will be borrowing "very little" in the credit markets during the next 18 months, and predicted interest rates would fall.

Miller also backed away from an earlier estimate that inflation would slow to 11 percent this year. He told an audience at the National Press Club he now thinks it is possible that inflation will be 11 percent to 12 percent in 1980.

The developments came as, separately, Senate Budget Committee Chairman Edmund S. Muskie (D-Maine) proposed that his panel recommend a $16 billion tax cut for next January, provided that Congress balances the fiscal 1981 budget.

The House Budget Committee proposed a similar step last week. The strategy is to earmark the new revenues from Carter's $11 billion oil-import fee so lawmakers can't use them to balance the budget, and must vote spending cuts.

The panel also agreed, 12 to 3, to hold defense spending for this fiscal year to the $120.9 billion ceiling Congress set last September. The move would deny the Pentagon $7.1 billion in supplemental appropriations.

Meanwhile, former Federal Reserve Board chairman Arthur F. Burns criticized Carter's new anti-inflation policy, and called for repeal of the 1969 law authorizing the credit controls the president has imposed.

Burns said the 1969 legislation has "put dictatorial power" in the hands of the Fed, which must administer the restrictions. He predicted that Carter's current anti-inflation plan would only hasten recession.

Separately, House liberals, upset by a House Budget Committee resolution recommending sharp cuts in social programs, began pushing to delay the measure in hopes of building pressure to undo some of the reductions.

In testimony before the House Rules Committee, the liberals sought strict enforcement of a four-day layover rule that would put off any floor action on the fiscal 1981 budget until after the Easter recess.

Their strategy is to delay any floor debate until constituent groups that would be affected by the cuts have time to muster their opposition. Budget Committee leaders want prompt action to continue momentum for budget cutting.

The Rules panel is expected to decide the issue on Monday after consultations with the House Democratic leadership. Sources said much of the outcome will depend on House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.).

House leaders already have tried to head off delay by asking the Rules panel to allow separate floor votes on amendments by five opposition groups -- the Black Caucus, House Post Office Committee, defense backers, Republicans and liberals.

The administration's request for companies to moderate their price increases came in the form of a tightening of Carter's price guidelines. The price standards are voluntary, and have been breached by some firms.

Under previous rules, companies could raise prices anytime they wished and still be considered in compliance as long as their average increase from late 1978 to late 1980 did not exceed their price hikes for 1976-77.

Yesterday, the council asked companies to take only half their remaining permissible increases in the April-June quarter and postpone the remainder to the July-September period -- in effect spreading the hikes evenly over two quarters.

Council Director R. Robert Russell said the action was necessary because some firms still weren't convinced the administration had rejected controls and apparently were preparing to raise prices sharply in order to beat them.

The council last week listed several key industries it said were raising prices more rapidly than would be considered normal -- including airlines, paper producers, cement-makers, hotels, food processors and retailers.

Russell did not say which firms or industries were planning big price hikes for next week. However, he said the agency's day-to-day contacts with dozens of corporations had convinced officials such a move was in the offing.