A House committee yesterday completed final action on President Carter's Civil Service revision bill, greatly altering the legislation and loading it with "Christmas Tree ornaments," but also giving the president much of what he wanted.

Some members of the committee termed the action a "significant victory" for the president and predicted that some of the amendments considered extraneous to the bill would be knocked off on the floor of the House.

In a major actions the committee voted yesterday to expand the power of federal employe unions beyond what Carter has said he could support.

The House Post Office and Civil Service Committee stopped short, however, of approving the most controversial of the proposals advanced by labor supporters on the panel. That was an "agency shop" proposal that would have required nonunion members to pay dues to the union.

The committee version of the bill would for the first time give 3,500 federal bargaining units the right to bargain on government-wide regulations affecting promotion standards, the number and type of employes an agency puts on a job, classification of jobs, travel expenses and standards for layoffs.

The bill would not give unions the right to bargain for pay and benefits.

The labor relations amendment represented the middle ground that was critical to getting the bill out of the committee, said committee vice chairman Morris K. Udall (D-Ariz.), who introduced the amendments.

The committee also added to the bill amendments that would:

Revise the Hatch Act to enable federal employes to take an active role in partisan politics.

Reduce work hours of federal firefighters (a measure vetoed recently by Carter).

Restrict a key portion of the president's bill dealing with the proposed Senior Executive Service to an experimental period of about two years. Carter had proposed to create such a service to increase the mobility and incentives of top federal managers.

The addition of the controversial Hatch Act revisions, which have long been a priority of organized labor, prompted Republicans on the committee who have supported the president's bill to defect in protest.

As a result, the amendment - which guts Carter's proposed executive service - was approved by the committee without the Republican votes needed to defeat it. The SES amendment was introduced by Rep. Gladys Noon Spellman (D-Md.).

"We have the ingredients of a good civil service reform bill here," Udall said afterward Udall has served as a mediator among the various factions on the committee that had threatened to sink the bill.

He noted the bill had stirred "strong feelings" among members of the committee, many of whom represent federal employe constituencies. He said he thought that most of the "ornaments" on the bill will come out and that there is a "good chance of getting the bill on the president's desk.

Rep. Stephen Solarz (D-N.Y.), a strong labor supporter on the committee, said afterward that the committee action was a "great victory for the president and gives him 80 percent of what he asked for."

Civil Service Commission Chairman Alan Campbell said that, while the House committee version of the bill is much further from the president's position than the Senate version, he is optimistic about prospects for getting the desired changes on the floor or in conference. He said that separating Hatch Act revision from the civil service revision bill is crucial.