A decision by the ANC to deal with the row between United Democratic Movement leader Bantu Holomisa and Speaker Frene Ginwala in a debate is likely to have far-reaching consequences for parliamentary democracy, opposition parties say.

Holomisa, in an open letter to Ginwala, accused her of bias in the arms deal investigation. She says his letter defamed her.

The chairperson of parliament's watchdog public accounts committee, Gavin Woods, has accused Ginwala of sidelining his committee in the arms deal investigation, while Democratic Alliance leader Tony Leon has lambasted the speaker for her actions.

Opposition parties have called for a parliamentary committee to be established to investigate Holomisa's claims and the speaker's role in the matter.

Not be correct for her to defend herself

The ANC, however, had resolved at its weekly parliamentary caucus meeting on Thursday to "call for a vote of confidence in the speaker" in the debate, to be held next week, caucus chairperson Thabang Makwetla said.

It was not clear whether the speaker would participate or chair the debate, but Makwetla believed it would not be correct for her to defend herself.

Opposition parties said a debate would not clarify Ginwala's position and could set an unfortunate precedent about the speaker's role in such matters.

Some indicated that they might want to boycott the debate.

Pan-Africanist Congress chief whip Patricia de Lille said a debate would not resolve the issues. It would degenerate into a "free for all" that would leave "the speaker and the speaker's office" open to "serious attack".

The Inkatha Freedom Party has supported the ANC's call for a debate. 

With acknowledgment to Andre Koopman and Independent Online.