Three political parties have expressed concern and outrage about the use of the slogan "Kill the Boer, kill the farmer" at the funeral of African National Congress MP Peter Mokaba.

The Afrikaner Eenheidsbeweging (AEB) added its voice on Sunday night to the Democratic Alliance (DA) and the Freedom Front (FF), objecting to the use of the slogan and condemning it as hate speech.

AEB leader Cassie Aucamp said his party would refer the use of the slogan to the SA Human Rights Commission (SAHRC).

He said the slogan, which was made popular by Mokaba, had previously been referred to the commission for a decision on whether it was hate speech or not. At the time the commission found that it was not hate speech if seen against the political background of that era.

Aucamp said the commission would have to answer the question if the slogan, seen in the current political context, was still not hate speech.

He said what worried him even more was the fact that President Thabo Mbeki had been present at the funeral where the slogan was chanted and apparently did nothing to stop it.

He said the AEB would also raise the subject in parliament during Mbeki's budget vote this week.

The FF also vowed to a lay a complaint with the SAHRC against the ANC.

FF leader Pieter Mulder accused the ANC's leadership of double standards when it came to condemning racism.

In his reaction, DA leader Tony Leon sharply criticised the government's failure to react.

Leon said farmers were being murdered at a terrible rate - last year alone more than 900 farms were attacked and 140 farmers murdered - and the government had done nothing to stop it.

- Sapa