President Ford proposed and the Senate quickly approved yesterday a bill that would make Vice President Rockefeller, Secretary of State Henry A. Kissinger and Treasury Secretary William E. Simon eligible for Secret Service protection for six months after leaving office.

Kissinger is known to want Secret Service protection, a spokesman for Simon said yesterday he would refuse continued protection, and Rockefeller could not be reached but is expected to accept. Rockefeller has long employed private guards.

Kissinger is the prime mover behind the unprecedented extension of Secret Service protection to former Cabinet officers.

He gave the impression to those watching him during his years in office that he delighted in the services that Secret Service agents provide and well-informed sources say he is reluctant to give up the Secret Service cars and chauffeurs that would smooth his way through private life.

One plan sent to the Office of Management and Budget for its consideration recently would cost $6.8 million a year for future protection of Kissinger and his wife, Nancy, according to an informed source.

On Wednesday, State Department spokesman Robert Funseth implied that the Secret Service had suggested continued protection for Kissinger because of recent threats against him.

Jack Warner, a spokesman for the Secret Service, yesterday denied that implication. "The Secret Service never suggests legislation that creates obligations," he said.

The New York Daily News quoted State Department sources yesterday as saying that a clique of Israeli right-wing extremists had offered under-world "hit men" $150,000 to assassinate Kissinger.

Funseth followed publication of that story by denying that the State Department had ever been informed of any threats involving Israeli political parties, specifically including the party mentioned in the Daily News, Likud.

Funseth's statement was a departure from normal State Department policy not to comment on reports of specific threats against the Secretary.

Ford proposed offering Secret Service protection to the three men through July 20, and Senate Majority Leader Robert C. Byrd (D-W. Va.) and Minority Leader Howard H. Baker Jr. (R-Tenn.) sponsored the bill, which passed by voice vote.

The bill includes immediate family members as eligible for protection. The House was not in session when the bill passed the Senate, but is expected to give its approval quickly.

Senators favoring extending Kissinger's protection beyond six months made it clear yesterday that they will draft such a proposal before the temporary protection they voted for yesterday expires.

The Secret Service refuses to disclose the number of agents needed to give one man round-the-clock protection, nor will it put a dollar figure on the cost.