In its final act before a new mayor and Town Council start their terms, Somerset's governing body last week called on the governments of the United States and the Soviet Union to halt the buildup of atomic weapons, and it set a June 1 referendum on a nuclear freeze.

The council's resolution asked for immediate negotiations on "a bilateral, verifiable freeze on testing, production and deployment of nuclear weapon systems" and a "subsequent reduction of existing nuclear weapons."

Outgoing Mayor Walter J. Behr said the council also approved a community forum to take place on the same day as the referendum vote. Jeremy J. Stone, a town resident and head of the Federation of American Scientists, will speak in support of the freeze, Behr said. A nine-member citizens committee is asking the Reagan administration to dispatch a representative to present the administration's arms policy.

The one-hour debate is scheduled to begin at 7 p.m. June 1 and will be followed by another hour of questions and answers. Voting on the referendum will be from 7 to 10 p.m. the same night. Both the forum and the election will be held at Somerset Elementary School, 5811 Warwick Place, according to Town Clerk-Treasurer Marty Cline.

In other action, the council set rules for those using facilities at Town Hall, which opened recently at 4510 Cumberland Ave. The newly renovated Victorian house features a community meeting room, which can be rented by community groups. Behr said the council approved rental fees of $50 an evening or, for long-running events like classes, $5 an hour.