Trade union Solidarity laid a charge of contempt of court against ANC Youth League president Julius Malema for singing the "shoot the boer" in Zimbabwe.

The charge was laid at the Brooklyn police station in Pretoria just after 3pm on Wednesday, spokesperson Willie Spies said.

"The court order that was granted on 1 April was very clear that Malema may not sing the particular song or use any related language (inciting violence)."

Malema sang the song on his tour in Zimbabwe over the weekend.

"He said the court order doesn't concern him in Zimbabwe and he also attacked the court, saying it was a relic of the apartheid government and they (the ANCYL) would continue the struggle against the justice system."

The contempt of court charges relate to the song and his statements about the court.

"The court order was issued against him as a person and follows him wherever he travels."

Spies said Malema knew what he was doing when he sang the song.

"According to the law, if you are aware of what you are doing and you know what the consequences from your actions will be, and you continue doing it, you have to carry the consequences."

He said Malema sang the song in front of SABC cameras, knowing it would be shown in South Africa.

"We are absolutely convinced that he is guilty," he said.

The case would have to be investigated by the police and presented to the Director of Public Prosecutions, who will have to decide whether Malema should be prosecuted or not.