Cape Town - United Democratic Movement leader Bantu Holomisa says he will not apologise to National Assembly Speaker Frene Ginwala for accusing her of interfering in the probe into the multi-billion arms deal.

This is despite a demand from Ginwala, made through her lawyers, that he retract the claim and issue an apology.

Holomisa's refusal could pave the way for Ginwala to institute legal action against the UDM leader.

In a written reply to a letter from Ginwala's attorneys - which demands a response from Holomisa "by no later than May 31" - Holomisa says: "We cannot reconcile her decision for a parliamentary process on the matter with her instruction to you demanding a retraction of the so-called allegations against her..."

Holomisa's reply also questions whether a parliamentary debate on the matter, scheduled for June 7, would be scrapped should the allegations be retracted.

Ginwala has repeatedly warned that Holomisa has "laid himself wide open" for litigation.

In an open letter to the media and diplomats earlier this month, Holomisa accused Ginwala (ANC) of, among other things, dereliction of duty and bias because of her interventions in Parliament.

In response, Ginwala urged MPs to examine the allegations.

The African National Congress and IFP parliamentary caucuses decided last week to call for a debate in Parliament on Holomisa's claims, despite calls from most opposition parties for a committee to be set up to investigate the matter.

"Sue or not, I will not retract what I said," Holomisa told Sapa on Thursday.

He said Ginwala had decided on a parliamentary process to deal with the claims, and this should be carried out.

However, there was insufficient time allocated to his party to substantiate the allegations.

The Chief Whip of the majority party had not responded to a request he had made for more than the four minutes - of the 102-minute debate - allocated to the UDM.

"What can you do in four minutes. The debate is about what I said, so I feel I should have been given more time... this is not unprecedented."

He would find it difficult to substantiate the claims in four minutes, Holomisa said.

Ginwala's lawyers letter to Holomisa - dated May 24 - says the allegations were not made in the context of parliamentary privilege, and were defamatory.

"Our client reserves her right to take any further legal action she deems necessary.

"She rejects the allegations and is extremely upset and outraged over the imputations raised about her character, especially in her role as the presiding officer of the House.

"Our client has instructed us to demand, as we hereby do, that you retract the allegations made against her in your open letter, and distribute an apology to all of the parties to whom your open letter was circulated."

The lawyer acting for Ginwala, Anton Steenkamp, was not available for comment.

Parliament's public accounts committee (Scopa) chairman Gavin Woods earlier this month also refused to apologise for publicly criticising Ginwala regarding the arms deal.

The Speaker had written to Woods demanding that he apologise for comments made in the media claiming she had attempted to sideline the committee from the probe.

With acknowledgment to Sapa and News24.