Johannesburg - The SA Communist Party on Thursday said DA MP Mike Waters must resign over a picture he tweeted.
"[The SACP] calls on Mike Waters to resign, failing which the DA must show seriousness and remove him as a public representative," SACP spokesperson Alex Mashilo said in a statement.
"Our Parliament is not a place for racism and racists," he said.
On Monday, Waters posted a picture, on social network Twitter, of dogs queuing to urinate on a photograph of president Jacob Zuma propped up against a tree.
A caption on the picture reads: "Voting Day. Make your Mark".
Responding to the SACP's call, Democratic Alliance Chief Whip John Steenhuizen said the tweet was "certainly regrettable and ill-advised".
He said Waters had acknowledged this, deleted the tweet, and apologised.
"We believe the matter rests there. We don't think it is in the purview of other organisations to tell us who we should be hiring and firing."
Mashilo said the Democratic Alliance's "automatic acceptance" of an apology by Waters was "a whitewash and smokescreen for racism".
He said the SACP would complain to the SA Human Rights Commission about the tweet.
On Wednesday, the ANC laid a formal complaint with the commission about material, including the tweet, that it deemed racist and insulting, and which it believed denied ANC voters their rights.
Previously, ANC spokesperson Zizi Kodwa said the tweet indicated the DA saw blacks as "sub-human... dogs".