The Democratic Alliance Youth has challenged ANC Youth League president Julius Malema to a public debate.

"We are challenging Malema to a public debate... Just name the time and place Julius," said DA Youth national leader Khume Ramulifho, in a statement.

This comes after a Sunday Times story that Malema called DA leader Helen Zille a "racist, colonialist and imperialist", at an African National Congress rally held at Cato Manor, Durban on Saturday.

Malema also said Zille's deputy Joe Seremane's "role is to smile at the madam every time".

The DA said Malema had bitten off more than he could chew by attacking its leaders.

"In classic Malema-style his ridiculous diatribe reveals more about his own inadequacies than it does about the intended victims of his attack.

"In response to his vacuous and insulting remarks about Zille and Seremane I would like to formally challenge Malema to a public debate," said Ramulifho.