President Jacob Zuma must intervene in the Western Cape's gang and drug crisis, the Congress of SA Trade Unions said on Wednesday.

In an open letter, Cosatu's provincial secretary Tony Ehrenreich asked President Jacob Zuma to urge premier Helen Zille to display greater leadership before it was too late.

"There is a clear absence of leadership on this matter of gangs and drugs, and calling for the deployment of the army without a coherent plan is just a populist way to deflect responsibility for resolving the crisis," he said.

"The situation is without doubt dire, as the bodies pile up and people are virtual prisoners in their own homes. The provincial government, the city of Cape Town and the police services have been unable to assist the people of the Cape Flats."

He called on Zuma to craft a solution to the crisis.

In a letter to the president on Monday, Zille asked for defence force members to be deployed to Lavender Hill and Hanover Park, which had both seen a "serious spike" in gang-related deaths.

At least 23 people, including seven children, had died as a result of gang violence in recent months.

"While the SA police service have deployed extra resources to these areas, gang violence has continued unabated. It is clear that the current situation is beyond the capacity of the SAPS to control," she said.

She said the army would restore order and allow police to effectively conduct investigations.

In her letter, Zille said the deployment of the army in gang hotspots over December had resulted in a marked improvement in safety levels.