President Carter has quietly signed into a law a bill providing for a veterans pension increase that opponents say violates the president's anti-inflation program and is unfair to disabled combat veterans.

White House officials yesterday denied the charges and asserted that the legislation will bring badly needed reforms to the pension program before millions of World War II veterans become elibible for its benefits.

Carter signed the bill without ceremony Saturday, 11 days after announcing his new anti-inflation program, of which a central goal is restraining federal spending. The White House denies the bill will have an inflationary effect.

At Camp David, meanwhile, Carter was deciding last night whether to sign or veto a bill to extend and expand federal programs for the handicapped - a measure some aides have also criticized as inflationary.

White House officials said they did not expect Carter's decision to be announced until today.

The dispute over the pension bill, enacted overwhelmingly at the last minute by the election-year Congress, essentially was between the White House and the Council of Vietnam Veterans, which had urged the president to veto the measure.

The bill would provide up to 82 percent increases in pensions of indigent veterans whose disabilities are not service-related, including veterans who are 65 or older and considered 100 percent disabled. It is estimated that it will lift benefit outlays $524 million beyond where they would otherwise be in fiscal 1980, and about $2 billion beyond their otherwise likely level through fiscal 1983.

The Vietnam veterans group charged that in approving such substantial increases, Congress and Carter are providing higher benefits to retired veterans who were never in combat than to a disabled combat veteran, who receives benefits under a separate compensation program.

Moreover, they point to a Congressional Budget Office estimate that it could cost $30 billion over the succeeding five years if Congress next year increases the compensation benefits to the wartime disabled veterans above the new pension benefit levels.

White House officials, however, argued that, by enacting a number of "reforms" of the pension system, the legislation signed by Carter will save the government money over the long term. Chief among these "reforms," they said, was a strict limit on the types of outside income a veteran could receive and remain eligible for the pension.

They also argued that, at the president's request, a congressional conference committee had cut the benefit levels initially passed by the House and the Senate and that it is by no means certain that Congress will enact a similarly large increase in the compensation program next year.

About 150 demonstrators held a vigil yesterday afternoon in front of the White House urging Carter to ignore the recommendation of the Office of Management and Budget and sign the four-year $5 billion measure to expand government programs for the handicapped.

Susan Lotempio, a staff member of Mainstream, a nonprofit organization dealing with the rights of handicapped people cited OMB's objections to the cost of the legislation said "I think it's more inflationary to keep handicapped people in welfare. Loss of the bill would mean fewer legal rights and less of a chance for independence for handicapped."

Government sources said that Health, Education and Welfare Secretary Joseph A. Califano, Jr. domestic adviser Stuart Eizenstat and White House congressional liaison Frank Moore had recommended that Carter sign the bill.

Besides extending vocational rehabilitation grounds to states, the bill would create a National Institute for Handicapped Research as an agency in HEW separate from the Rehabilitation Service Administration, which currently administers programs for the handicapped.

The legislation also would expand services that promote independent living for handicapped people and extend them to those who are so severely disabled that they cannot be expected to hold jobs. Congress provided $80 million this year for such services, which would include training the handicapped to get around the house and building homes for groups of disabled people.

The bill would set up demonstration projects with business and industry to create more jobs for the handicapped, and it would make it easier for the disabled to bring cases alleging discrimination to court and to HEW's attention.

OMB reportedly does not like the bill's system of providing state grants by "entitlements," which means that the administration would have to pay the sums Congress set in the authorization bill rather than wait for a separate appropriations measure.

Sources said OMB also objected that the bill, in creating the separate research institute, was unnecessarily adding a layer to the bureaucracy, and it noted that the measure would create more paperwork for states in applying for grants.

The bill authorizes $1.2 billion for fiscal 1979, $250 million more than Carter requested; $1.35 billion for 1980; $1.4 billion for 1981, and $1.3 billion for 1982.