AfriForum and TAU SA are preparing to lay charges against ANC Youth League deputy president Ronald Lamola over comments he made about land reform, the groups said on Wednesday.
"AfriForum intends to lay charges against Lamola at both the Equality Court and the police in order to ensure that inciting statements of this nature are called to order," the organisation's legal representative Willie Spies said in a statement.
He said Lamola's comments amounted to hate speech and fell within the definitions of incitement to violence.
The Transvaal Agricultural Union (TAU SA) said it was "disgusted" by Lamola's comments and would file a complaint to the SA Human Rights Commission.
"TAU SA has instructed its legal team to start with the strongest possible measures against Lamola, the ANC Youth League, the ANC and its president."
On Tuesday, Lamola said the Constitution must be changed to allow the expropriation of land without compensation.
He warned that if white South Africans did not hand land over to poor blacks, there could be land invasions like those that took place in Zimbabwe.
Spies said Lamola specifically referred to "the van Tonders and the van der Merwes on farms" and warned that their safety could not be guaranteed.
African National Congress Youth League spokeswoman Magdalene Moonsamy said the groups needed to be "ready for the fight of their lives".
"We welcome this battle, and we will not retreat. We are adamant that this issue of land cannot be negotiated, and at no point will we back down," she said.
"It is fine if certain structures in Afrikaner society want to lay complaints - we will find and meet them wherever they do so."
The ANCYL later issued a statement calling AfriForum "the defender of white privilege".
"We reaffirm the statement made by [Lamola] that those who continue to hold land which was illegally and immorally taken away from the indigenous people of South Africa must voluntarily co-operate with the ANC-led government [to] ensure swift and equitable redistribution of such land to the masses of our people."
The league again warned it might not be able to stem the impatience of the millions of landless South Africans.
"Such a precautionary note raising the hopeless plight of our people, blacks in general and Africans in particular, can only be construed as an incitement to violence... by those hell-bent to protect white minority privilege at the expense of the black majority."
The league said if it was to achieve economic freedom there needed to be "urgent, unapologetic and radical land redistribution".