Cape Town – The Democratic Alliance's Federal Legal Commission on Friday set out a timeline for Western Cape Premier Helen Zille's disciplinary hearing, which will see a pre-meeting hearing take place at the end of the month.

Glynnis Breytenbach, the head of the commission, said all parties would sign confidentiality agreements by June 13, to "protect the integrity of the hearing".

The next step would then be the submission of all documents pertaining to the disciplinary case to the commission by June 23.

Following that, the pre-hearing would be held on June 30, to confirm the readiness of those involved to proceed and to deal with any preliminary points, Breytenbach said.

Zille was this week suspended from the party pending the disciplinary process. It stems from a series of tweets in March in which she appeared to defends aspects of the legacy of colonialism.

DA suspends Helen Zille over colonialism tweets

DA leader Mmusi Maimane laid a formal complaint, charging that Zille's remarks had brought the party into disrepute.

He announced last weekend that she would be suspended as she rejected his call for her to issue an unreserved apology.

Zille has hit back saying that Maimane had in doing so flouted the party rules as he made the announcement without first allowing her to submit reasons why she should not be suspended. She said it also meant that her suspension – which was eventually confirmed on Thursday – was a foregone conclusion, regardless of how strong her defence might be.

“The failure to observe due constitutional process in terms of section 3.6.3 of the DA constitution, has rendered the exercise of my right to representation hollow, as there is little chance of the DA Fedex publicly embarrassing the leader through being influenced by the legality of my submission, no matter how cogent it is,” Zille said in her submission to the party, which she also made public.

She has added that she was consulting lawyers and might take legal action against the DA's federal executive for the manner in which she was suspended.

The battle between Zille and her successor and former protege escalated shortly after Maimane's initial complaint when Zille sought to defend her remarks instead of retracting them.

This included an article she wrote for the Daily Maverick that appeared to repeat the initial, problematic view.

Malema wants Zille fired or EFF will quit coalition

In the article, Zille explained that she had returned from a visit to Singapore, where she was struck by the efficiency, to struggle to find milk or newspapers in the VIP lounge of OR Tambo Airport.

She added that she had not defended colonialism but said its entire legacy was not negative. Maimane told the media this had exacerbated the damage and had therefore been added to his initial referral to disciplinary authorities in the party.

Zille this week suggested that Maimane may be "punishing" her for not relinquishing the post of premier.