A new congressional mood toward peacetime military spending is now being translated into recommendations to increase President Carter's defense budget.

The House Armed Services Committee on Wednesday voted to add $2.6 billion to Carter's defense budget of $128.4 billion (Counting nuclear warheads supplied by the Energy Department).

The Seate Armed Services Committee is also weighing an increase, with the Republican minority there pressing for an addition of $6 billion.

"The mood up here has definitely swung from cutting the defense budget to adding to it," said one veteran staffer on a congressional military committee.

Although the Appropriations committees of both the House and Senate traditionally are less generous than the Armed Services committees which set ceilings on how much can appropriated, they are not expected to recommend sizable cuts in the president's defense request this year, either.

The military and other congressional committees are required to inform the House and Senate Budget committees by next Wednesday what total amount they estimate will be needed for national defense and other government activities in fiscal 1979, which begin Oct. 1.

The Republican effort on the Senate Armed Services Committee indicates that the Party believes that voters in this election year favor high military budgets, an issue GOP presidential challenger Ronald Reagan used in 1976 against President Ford. Sen. John G. Tower of Texas, ranking Republican on the Senate Armed Services Committee, is chairman of the Senate Republican Policy Committee.

Carter said during his presidental election campaign that defense spending could safely be cut $5 billion to $7 billion annually.

The house Armed Services Committee, in voting for a net increase of $2.6 billion to bring the fiscal 1979 national defense budget up to $131 billion, challenged Carter on several specifies within his military budget as well as the total request.

The committee intends to state in the report explaining its recommended higher ceiling that another Nimitz-class nuclear-powered aircraft carrier should be built. Carter did not request any money for a new carrier, pending completion of a new study on the ships the Navy will need for the 1980s and 1990s.

The house committee , besides recommending $2.1 billion for another Nimitz earmarked about $1 billion for a nuclear cruiser; added money to build more Navy F14 fighter planes than the administration requested and to keep the A7 attack plane program alive.

The Carter defense budget calls for building 24 F14 aircraft and halting production on the A7, recommendations that Navy leaders tried vainly to reverse during the drafting of the fiscal 1979 miltary budget.

The Grumman F14 is made in Long Island and the A7 in Dallas. New York and Texas lawmakers are fighting for additional money for those programs.

To offset additions for the carrier, cruiser and aircraft, the House Armed Services Committee voted to provide less money for the Trident missile submarine on the ground it is too far behind schedule to use all the funds Carter has requested, $1.2 billion.

Other cuts recommended by the House committee are in such noncombat requests as trucks. Also, the committee recommended a limitation a $150 million stock fund in the Pentagon budget.

The Senate Armed Services Committee is scheduled to meet Monday to vote on how much money should be spent on national defense in fiscal 1979.