Majority Leader James C. Wright (D-Tex.) said yesterday that the House will not go along with any effort to freeze Social Security cost-of-living adjustments for a year to help reduce the federal deficit.

President Reagan said at a news conference Wednesday night that he might consider a one-year deferral of Social Security cost-of-living adjustments (COLAs) if "faced with an overwhelming bipartisan majority in both houses in support of that."

Senate Republican leaders, attempting to draft an alternative to Reagan's fiscal 1986 budget that would produce greater reductions in the deficit, have suggested a cancellation of the COLAs next year as part of a one-year spending freeze.

A study released yesterday by an economic forecasting firm show that a one-year freeze of the COLAs would result in a half-million older Americans, mainly elderly women, being pushed below the poverty line in 1986. More than three-fifths of that half-million would be 72 years old or older, the study found. The COLAs are paid each year to prevent Social Security benefits from being eroded by inflation.

Reagan "seems to be under some strange illusion . . . that an overpowering congressional mandate is going to force him to break his promise to protect the cost-of-living adjustments for the Social Security recipients," Wright said in an interview yesterday morning on NBC's "Today" show.

"I can't speak for the Senate, but I can assure him that the House will be not party to any effort such as that. We're going to help him keep his promise to the retirees of the United States," he said.

During his reelection campaign Reagan promised not to tamper with Social Security, including the annual cost-of-living adjustment. When asked Wednesday night whether Social Security was still off-limits, Reagan said that if Congress insisted, "I would have to look at that situation and what I was faced with, with regard to a possible congressional mandate."

Rep. Robert T. Matsui (D-Calif.), a member of the House Ways and Means subcommittee on Social Security, said Reagan would have to initiate and push for a freeze on cost-of-living adjustments before the Democrats would even look at it "and even then I'm not so sure of it. I find it hard to believe he thinks. . . he can get his way out of his campaign promise."

On the Republican side, a top aide to House Minority Leader Robert H. Michel (R-Ill.) said House Republicans are unlikely to support any tinkering with Social Security.

"People remember what happened in 1982 when the Republicans lost 26 House seats in large part because of voter concerns that the GOP and Reagan would cut Social Security ," the aide said. "Put your hand on the stove once and get burned it's an accident, a second time it's stupidity."

The study released yesterday, which was prepared by Data Resources Inc. for the American Association of Retired Persons, found that if the cost-of-living adjustment for 1986 were paid in full -- using an inflation rate of 3.9 percent -- the number of people 62 and older below the government's official povety line would be 4.6 million.

But if Congress approved a living-cost adjustment that was 3 percent below the inflation rate -- one of the options being considered by Senate Republicans -- the number of people 62 and over falling below the poverty line would rise by 500,000 to 5.1 million.

The study said a cancellation of the cost-of-living adjustment would push even more people into poverty but it did not estimate the number.

Of the 500,000 added to the ranks of those officially in poverty under the second calculation, about 180,000 would be elderly single women and 100,000 elderly married women, the study found.

Three-fifths of the 500,000 would be men and women who are 72 years old or older.

The study also found that if the annual COLA increase were held to 3 percentage points below inflation through 1990, about 6.9 million senior citizens would have incomes below the current poverty line. If the full COLA were paid only 4.6 million would be below the poverty line, it said.