Conflict between the DA and Cosatu at a protest in Johannesburg was a politically significant event, Cosatu general secretary Zwelinzima Vavi said on Wednesday.

The DA-organised march was an attempt to pit workers against workers when it was in fact a class battle, he said in Johannesburg at an international meeting of trade union federations hosted by the Congress of SA Trade Unions.

He said the confrontation with the Democratic Alliance made clear the differences between the two groups, and that their guiding principles were "fundamentally different".

"Yesterday (Tuesday) was significant because it showed the frustration of the most marginalised in our society."

Rocks flew when DA supporters marched to express support for a youth wage subsidy near Cosatu headquarters in the city centre. Police used teargas and water cannons to disperse Cosatu members.

The confrontation was an indication of what could come unless joblessness and poverty were not addressed in a radical and different way.

"We are sitting on a ticking bomb," Vavi said.

"Unemployment and poverty are worse now than ever before."

Workers in minibus taxis, described by Vavi as "glass coffins", on their way to work, saw the wealth of others and their frustration was growing.

He said the DA protest was an attempt by a political party that represented the rich and company bosses to exploit the country's poor.

The most critical issues facing the country were now deepening unemployment, dehumanising poverty, and inequality.

"The leadership debate and Mangaung is not the major focus," Vavi said, referring to the venue of the ANC's elective conference later this year.

"We need to decide where we are going and bring back the Freedom Charter."

He chastised the media for what he labelled as one-sided reporting on Tuesday's protest, claiming the DA had come to the protest with a truckload of rocks.

Four Cosatu members were badly injured, which was unreported, Vavi claimed.

"I condemn violence, all violence even from Cosatu members. It is not good for anyone."