"For too long, Cosatu (the Congress of SA Trade Unions) and its affiliates have been allowed to engage in violent and chaotic strikes without any repercussions," DA MP Ian Ollis said.

In a statement, he said the ruling set a precedent that would force the unions to keep better discipline at marches, pickets and strikes.

The DA wanted the ruling to apply to any and all cases of violent strikes which resulted in damage to property.

"I will, therefore, continue pushing for an amendment to the Labour Relations Act to explicitly hold unions liable for damage during strikes, in any and all cases.

"This ruling must be written into the letter of the law to stop the practice of violent, chaotic and disorganised strikes once and for all," Ollis said.

The court ruled that the SA Transport and Allied Workers' Union was responsible for damages caused during a march in Cape Town in May 2006.

It found that the Regulation of Gatherings Act afforded victims effective recourse when a gathering became destructive and resulted in injury, loss of property, or life.

"The organisations are intimately involved in the planning, supervision, and execution of the gathering, but the potential victims are not," Chief Justice Mogoeng Mogoeng said in the ruling.

"Because of this, the organisations would be in a better position than innocent victims to identify individuals or institutions which caused the damage."

He said Satawu had the opportunity of a "soft landing" if it could track down those responsible for the damage caused during the protest and recoup its loss from them.

The union appealed this decision twice and on both occasions it was turned down.