Congress was urged yesterday to give voters the right to repeal measures passed by Congress as well as to enact federal legislation at the polls.

"I think they go hand in hand," consumer advocate Ralph Nader told a hearing by the Senate subcommittee on the Constitution.

Nader and other witnesses were asked by Sen. James Abourezk (D-S.D.), principal sponsor of a constitutional amendment to establish a national right of initiative, whether the power of referendum, or repeal, should be added to it.

Nader said either the initiative or referendum should be accompanied by controls designed to equalize campaign spending and access to the information media by supporters and opponents of issues.

"Given these safeguards," he said, "I don't see any reason why the referendum power should be deleted."

Los Angeles County Supervisor Baxter Ward testified that it would be an excellent idea to add a referendum feature.

Joyce Koupal of People's Lobby, a Los Angeles organization, said federal referendum provisions should be enacted with the initiative or shortly thereafter."

Abourezk's proposal does not include the referendum, but he said there had been "a good deal of comment" that it should be added.

As the subcommittee opened its hearings on the proposal Tuesday, Chairman Birch Bayh (D-Ind.) said he had "serious reservations" about adopting the initiative process, now in effect in 23 states, at the federal level.