The Defense Department plans to move 20,000 people and spend more than $1 billion a year if full deployment of the planned ground-launched cruise missiles takes place in Europe, according to recently released congressional testimony.

Congress has been trying to keep costs at a minimum because the United States is negotiating with the Soviet Union to eliminate or limit the number of cruise missiles to be deployed in five NATO countries.

But the administration is pressing for major expenditures on support facilities at the missile bases, in part to persuade the Soviets that the United States is serious about going ahead with the controversial missile plan. According to Rep. W.G. (Bill) Hefner (D-N.C.), chairman of the House Appropriations subcommittee on military construction, full deployment of 464 missiles at six bases "will move almost 20,000 U.S. personnel, dependents and civilians to Europe" and cost "more than $1 billion annually in operating and maintenance costs."

The estimates were given in a closed hearing before Hefner's subcommittee last March when Pentagon officials presented the first full picture of costs and personnel implications if the missile deployment begins as planned in December. The hearing record has since been published with some material deleted for security reasons.

During the session, Pentagon officials disclosed that construction activity or surveys have begun in all five countries scheduled to receive the missiles, including the Netherlands and Belgium, whose governments have not publicly approved deployment. Other cruise missile bases include one in Italy, one in West Germany and two in Britain.

According to Hefner, construction costs of the bases will total $1.2 billion, with the United States paying $950 million and the NATO allies the rest.

Part of the high construction cost, according to the Defense Department, stems from the need to build housing and other facilities for dependents of missile personnel in such out-of-the-way places as Comiso, Sicily, site of the Italian base. The fiscal 1984 request for $29.9 million for Comiso, for example, includes landscaping, a recreational club and swimming pool, a library, an arts and crafts shop, a bank and a credit union, facilities that would be abandoned if under any future agreement deployment does not take place.

The subcommittee last year took the position that construction outlays for the cruise missile bases should be kept to a minimum and limited to operational facilities in light of the U.S.-Soviet negotiations.

Administration witnesses during last March's closed session, however, disagreed.

The costly community support projects, Defense Department witnesses argued, are, like the missiles themselves, bargaining chips in the continuing talks with the Soviets at Geneva over the level of Euromissiles.

"Successful arms-control negotiations will be possible only if the Soviets are convinced we are prepared to go ahead with a full-scale deployment of these weapons along with a full complement of personnel," the department told the subcommittee in a written response to questions.

Also disclosed during the hearing:

* The Air Force has held "military discussions with deleted " in the Netherlands and conducted a preliminary survey of potential cruise missile basing sites there, even though its government has yet to approve basing cruise missiles on Dutch soil and a majority of the public has indicated opposition to deployment.

As a result, the Air Force is asking for $34 million in fiscal 1984 "as the minimum amount needed to begin construction in 1984 in order to meet the scheduled deleted operational capability" in the Netherlands.

* The Belgian government, which also has hesitated to support deployment publicly, has signed a construction agreement that allows work to begin at a designated air base site.

"Contract awards for demolition and site preparation in support of facility construction" in Belgium, "will be made by the end of fiscal 1983," according to the testimony. The $43.2 million requested in fiscal 1984 funds for the Belgian base will be used for "day-to-day operations of the base and the active duty military support personnel to be assigned."

* The proposed cruise missile base in West Germany is to be at a former U.S. Army Nike Hercules antiaircraft missile base since turned over to the Air Force. First construction funds totaling $22.3 million for this West German base are also included in the fiscal 1984 bill.

West Germany is also to receive the first of a scheduled 108 Pershing II missiles beginning in December. Those missiles, however, will replace already deployed Pershing 1a missiles on a one-for-one basis and will not require any major increase in personnel.