The Carter administration, concerned that it voluntary wage-price program may be losing credibility, is considering for the first time invoking formal sanctions against a major corporation -- Mobil Corp. -- charged with violating its price guidelines.

The administration's top-level Economic Policy Group is debating a proposal that would deny future federal contracts to Mobil, which was accused by the Council on Wage and Price Stability of overcharging customers $45 million.

Debarment of Mobil would mark the first-time in the 18-month history of the program that the White House has imposed sanctions against violators.

Although Carter served notice at the program's start he would deny contracts to violators who do $5 billion or more a year in business with the federal government, the administration has not yet done so.

Only two accused violators, Amerada Hess Oil Company and the Ford Motor Co., have had enough government contracts outstanding to be in danger of a cutoff. But Hess agreed soon after it was cited to come back into compliance.

The wage-price council has charged 12 corporations with violating the price guidlines and 11 others -- including Ford -- are accused of flouting the pay standards.

Mobil now has $145.1 million in outstanding government contracts, almost all with the Defense Department. However, these would not be affected by any cutoff, which would apply only to new contracts.

COWPS officials have recommended that Carter approve use of sanctions in part ot bolster the agency's enforcement image and help discourage further breaches of the guidelines by companies and unions.

Anti-inflation officials have expressed fears in recent weeks that some big firms are raising prices unnecessarily, apparently in anticipation of possible controls. They also fear a new round of big wage increases.

However, Carter and his top economic advisers are said to be moving slowly in deciding the issue, on grounds that the Mobil case is a difficult one and that any move to invoke sanctions might have political repercussions.

The administration's seven-month-old "national accord" with labor guarantees that the White House will not move against pay contracts that violate the guidelines as long as wage increases generally remain moderate.

And White House officials fear that members of the six-person Price Advisory Committee may walk out of the program if the administration imposes sanctions on price violators without also moving against pay violators.

Moreover, many analysts also have questioned the administration's charges against Mobil. The council's complaint primarily involves accounting practices for one quarter. Mobil was below the guidelines for the year.

White House anti-inflation czar Alfred E. Kahn hinted indirectly at the proposal yesterday, telling an audience of newspaper editors that the administration would "not shrink from confrontation where necessary."

Kahn told the editors yesterday that "if all else fails," the government still would use "denial of [federal] subsidies, protection and contracts. These are sanctions that we have never renounced," he said.

Kahn also disclosed that the council intends to meet with executives of the chemical industry in the next few weeks to discuss ways to pare price increases, now running at a 30 percent annual rate, in industrial chemicals over the past few months.

Kahn also raised the possibility that if inflation moderates in the months ahead, "we can, in fact, get interest rates down, and . . . possibly even avoid the recession that now seems to be imminent."

And he vigorously defended the administration's new budget-balancing proposals against charges that the spending cuts won't do much good, that the cutbacks aren't real and that the Federal Reserve Board is a villain.

The recent rise in interest rates is "not a diabolical intention on the part of [Fed chairman] Paul Volcker to make everyone suffer," Kahn told the group, "but rather the result of an insatiable demand for consumer credit."

Meanwhile, council officials said they are reviewing a proposal by the Pay Advisory Committee that would give that tripartite panel authority to decide whether specific pay settlements meet the guidelines, subject to agency agreement.

COWPS planners are said to be lukewarm about the plan, but are expected to approve it in part to maintain the administration's "accord" with organized labor. Labor leaders already are threatening to abandon the guidelines program.

Kahn's remarks generally squared with suggestions by chief White House economist Charles L. Schultze on Tuesday that inflation might well slow substantially later this year if energy prices and home mortgage interest rates moderate.

Schultze told a National Press Club audience that a 2-percentage-point drop in mortgage rates and a slowdown in energy price increases to a 20 percent annual rate could pare the rise in consumer prices to an annual rate of 8 percent.

Administration officials, including both Kahn and Schultze, have been cautioning that prices are likely to continue rising sharply for the next several months as recent interest rate hikes and oil price increases "filter through" the economy.