The chairman of the House Budget Committee said yesterday his panel will go along with President Carter's proposed $29 billion fiscal 1980 budget deficit, but warned the move would require larger cuts in social programs than Carter envisioned.

Rep. Robert N. Giaimo (D-Conn.) told reporters that because of new outlays for the Middle East peace package and higher energy costs, Congress would have to make additional cuts in other programs to stay within Carter's $29 billion deficit ceiling.

He listed as likely candidates for extra cuts the $6.9 billion general revenue-sharing program and other aid to states, counties and localities, and federally financed job programs. "The people from the cities," he said, "are going to be most unhappy."

Giaimo made his comments at a luncheon session as the Budget Committee prepared for hearings early next month to draft the new congressional budget resolution, which sets preliminary spending and revenue targets for Congress to follow on fiscal 1980 money bills.

Under the four-year-old congressional budget process, the panel must make formal recommendations by April 15 so the House and Senate can approve specific targets by the middle of May. The lawmakers then have a second chance in September to revise their preliminary ceilings.

Giaimo's assessment was certain to be a disappointment to liberals, who had hoped to persuade the Budget Committee to restore some of the cuts Carter proposed last January. The president's budget then called for an estimated $6.9 billion in cuts, all outside the defense area.

However, Giaimo said yesterday that, if anything, House leaders would have to work hard to fend off efforts by conservatives to slash the deficit still further during floor action. Republicans already have served notice they will make that a major issue.

On a related subject, Giaimo also expressed concern that some law-makers may back low-deficit figure in the budget resolution, but then vote for individual money bills that restore some of Carter's cuts, as they did last month on a measure involving nurses' training.

"If they go down that route, all they will do is prove the need for a constitutional amendment to balance the budget," he warned. Giaimo and other House leaders strongly oppose a balanced-budget amendment as unworkable and likely to cause fiscal chaos.

The Budget Committee chairman also was doubtful that the panel would chip away any further at defense spending, as it has in previous years. He said that even if the Budget Committee recommended such cuts, "I don't think we would have the votes for it" on the floor.

Rather, Giaimo said, House members have so changed their views on defense spending that the chamber may well end up increasing the Pentagon's budget this year, rather than cutting back on Carter's recommendations. "There's been a real shift," he said. "People are very concerned."

In his remarks yesterday, Giaimo appeared confident that Congress would agree to hold the deficit within the $29 billion Carter has requested, saying, "I think he's got a pretty good chance to make his figure stick," and "I don't think we could get any votes to increase it."

At the same time, he cautioned, the deficit could swell beyond the $29 billion limit if Carter's economic forecast proves too optimistic and a recession stunts revenues and output. "So far the economy is outperforming the president's assumptions," he said.

Giaimo told reporters he thought that with Democrats so divided, Republicants this year had a chance to exert unusual influence on the overall budget targets. "They know they can write the budget if they support the resolution," he said. "All they have to do is be reasonable."

He did not say how much more he thought Congress would have to cut domestic spending programs to meet the $29 billion deficit target, although he implied it could be as much as several billion dollars. He will make formal recommendations April 1.