The chairman of the Senate Intelligence Committee said last night that he and some other committee members are fed up sitting by like "potted palms" while lawyers question Lt. Col. Oliver L. North.

Sen. David L. Boren (D-Okla.) charged that the congressional committees investigating the Iran-contra affair have mishandled their nationally televised interrogation of North by allowing staff attorneys to question the former White House aide during his first three days of testimony.

Boren was particularly critical of House chief counsel John W. Nields Jr., who was the sole interrogator of North during his first two days of testimony. Boren said he thought committee members could have done a better job of focusing their questions.

Like other committee members, Boren reported that constituents have been flooding his congressional office with phone calls supportive of North and critical of the committees' inquiry.

North was questioned yesterday by House minority counsel George Van Cleve and by Senate chief counsel Arthur Liman. With Liman scheduled to resume his cross-examination of North this morning, the 26 committee members will not begin their questioning of North until later today.

Boren said he expects that by then, the public will feel that the committees had already kept "that poor man" at the witness table long enough.