Two men are presumed dead after they were swept off a bridge during a flash flood in Verulam, north of Durban, on Sunday night.

Parts of KwaZulu-Natal were battered by heavy rains, which caused extensive damage in many areas. The worst-hit areas were those north of the city.

Prem Balram, head of private security company Reaction Unit SA, said they received a call for assistance from a local councillor, who allegedly witnessed two men being washed off the bridge in Everest Heights in Verulam.

A team of policemen and Reaction Unit officers searched for the men without success.

"The search was called off due to the heavy current and poor light," said Balram.

Balram said a Rusa helicopter was dispatched on Monday morning to assist rescuers in their search.

It is understood that three people are unaccounted for in Verulam and nearby Blackburn.