Three policemen were injured and one alleged robber killed during an attempted bank robbery in Nongoma in northern KwaZulu-Natal on Friday, police said.

"One policeman was critically injured and two sustained minor injuries," said Superintendent Vincent Mdunge.

Mdunge said a group of men entered the First National Bank dressed in boiler suits similar to staff at the bank.

"It is alleged that these men held up staff with firearms and prevented them from raising the alarm," he said.

A bank employee managed to call the police but when police arrived the robbers began shooting at them. Police returned fire killing one man.

No arrests were made and the other robbers fled.

Police recovered two firearms and a Toyota Corolla used by the robbers.