The ruling Saenuri Party on Friday boycotted a hearing on the state spy agency's alleged meddling in last year's presidential election as it wrangled with opposition parties over whether the meeting should be open to the public.

The ruling party has argued that the hearing should be held behind closed doors because it is likely to touch on sensitive intelligence issues as lawmakers question National Intelligence Service (NIS) chief Nam Jae-joon and other officials of the spy agency in connection with the scandal.

Opposition parties have insisted that the hearing be open to the public so as to ensure its transparency.

The scandal centers on allegations that former NIS chief Won Sei-hoon ordered an online smear campaign to sway public opinion in favor of the ruling party ahead of last December's presidential election.

A parliamentary probe has been under way since early this month to determine the truth behind those allegations.

Friday's hearing was supposed to be the first time for the parliamentary investigative committee to question NIS officials in connection with the case.

Earlier this week, the committee held hearings with the Ministry of Justice and the National Police Agency over the scandal.

The hearing opened with only the opposition parties' investigative committee members in attendance. NIS officials were also absent from the meeting.

The opposition members immediately held a press conference condemning the boycott, saying they will charge Nam for boycotting the hearing without permission and take steps to impeach him. (Yonhap News)