DA leader Mmusi Maimane announced on Saturday that Western Cape Premier Helen Zille, a former party leader, has been suspended from the DA following her controversial tweets about colonialism.
Explaining his decision, Maimane said: "It has become clear that Premier Zille and I hold fundamentally different views on the direction we need to go."
The DA leader said he found her tweets on colonialism deeply offensive, but maintains he doesn't believe she's racist.
Maimane was speaking on Zille's suspension following the party's two-day Federal Executive meeting in Kempton Park.
He said Zille would not be removed as premier because that was a "legislative matter".
Zille's tweets after a visit to Singapore in March caused shockwaves as many demanded she be removed from her position as premier of the Western Cape.
It was clear Zille did not share the same attitude about the DA's mission for 2019, he said.
"Zille's social media commentary and public utterances in connection with colonialism undermine our reconciliation project. There is no question that Zille'a original tweets and subsequent justification have damaged our standing in public," said Maimane.
He said Zille refused to apologise to the country when he asked her to.
"In this period Zille has continued to damage the party with various pieces of communication that seek to undermine what we are trying to achieve," he said.
"Federal Executive has resolved to suspend Premier Zille from all party activities pending outcome of her disciplinary process."
Maimane did not give a date when Zille's disciplinary hearing would begin.
A storm erupted on March 15 after Zille sent out the following tweets in succession:
* Much to learn from Singapore, colonised for as long as SA, and under brutal occupation in WW2. Can we apply the lessons in our democracy?
* Singapore had no natural resources and 50 years ago was poorer than most African countries. Now they soar. What are the lessons?
#Maimane; 'It has become clear that Premier #Zille& I hold fundamentally different views on the direction we need to go' pic.twitter.com/pzp1Ogtlik
— Thulasizwe Simelane (@ThulasSims) June 3, 2017
* I think Singapore lessons are: 1) Meritocracy; 2) Multiculturalism; 3) Work ethic; 4) Open to globalism; 4) English. 5) Future orientation.
* Other reasons for Singapore’s success: Parents take responsibility for children, and build on valuable aspects of colonial heritage.
* For those claiming legacy of colonialism was ONLY negative, think of our independent judiciary, transport infrastructure, piped water etc.
* Would we have had a transition into specialised health care and medication without colonial influence? Just be honest, please.
Maimane says #Zille continued to damage party with various pieces of communication that undermined what the DA is trying to achieve #DAFedEx pic.twitter.com/EGY0dCY2nR
— Sikelelwa Mdingi (@SikiGeyaMdingi) June 3, 2017
* Getting onto an aeroplane now and won’t get onto the wi-fi so that I can cut off those who think EVERY aspect of colonial legacywas bad.
While Zille later apologised, the former DA leader was adamant her views on colonialism were misconstrued.
She added that there were many “falsehoods” in relation to the series of tweets sent out on lessons learnt from her recent visit to Singapore.
Last month, the South African Human Rights Commission initiated an investigation into the saga and provincial commissioner André Gaum said the probe was in response to several complaints from across the country.