Former Democratic Alliance (DA) leader Helen Zille has apologised to South Africans for her tweets justifying some aspects of colonialism.

"I realise my actions were insensitive to South Africans who suffered under colonial oppression," said Zille. She was speaking at a joint media briefing with party leader Mmusi Maimane in Rosebank on Tuesday.

In March, Zille tweeted that, "for those claiming the legacy of colonialism was only negative, think of our independent judiciary, transport infrastructure, piped water... etc".

She then went on a campaign across different media houses to defend her views, ignoring the advice of several leaders in the party, including Maimane and former leaders of the DA.

Last week, the party announced that Zille had been suspended pending disciplinary proceedings, which started on Friday, June 9.

The DA decided that Zille should vacate her positions on all decision making structures of the party, including the Federal Executive, the Federal Council and Provincial Council.

"This has not been an easy decision. The alternative was to become embroiled in a protracted legal battle in the lead up to the 2019 election," said Maimane.

The party leader, who said he was personally angered by Zille's tweets, said it was important for society to be mindful of the fact that colonialism was not a victimless crime.

"Many South Africans suffered directly under colonialism and apartheid, and continue to be disadvantaged by the legacy of colonialism and apartheid," said Maimane.

He also said the party would strive to build a future that is free of oppression.