Police are searching for three bank robbery suspects who were apparently sprung from Pollsmoor prison this week by men posing as police.

The three, already facing charges of escaping from custody following an incident six months ago, were expected to appear at the Wynberg Magistrate's Court on Wednesday.

"When the assigned police members arrived at Pollsmoor to transport the suspects to court, they were informed that the three were allegedly already taken to court," Superintendent Billy Jones said on Thursday.

"They failed to make an appearance in court and no-one could account for their whereabouts."

Jones said the circumstances surrounding the escape were being investigated.

He named the men as Thabo Mnkandla (32), Zain Sebata (24), and Brian Busani (29).

A correctional services staffer told Sapa that the men, whom he described as "high-profile offenders" were fetched from the prison on Wednesday morning by men claiming to be police, with what appeared to be police IDs, equipment and an apparent police vehicle.

"Serious loopholes"

"They must obviously have had information about how the system at the prison works," the source said.

"Everything in the handover was done according to correctional services policy, which shows there are serious loopholes."

In May this year the three men and two alleged accomplices broke out of the holding cells at the Athlone Magistrate's Court after overpowering a constable and seizing his service pistol.

One of the men pointed the pistol at the policeman and pulled the trigger repeatedly, but it turned out that the weapon was not loaded.

They were re-arrested after a period on the run.

At the time, police said they were planning to deploy specialised police officers to escort criminals in and out of court.

The three were originally arrested in connection with a robbery at the FNB bank at Vangate Mall in April.

They were also wanted in Gauteng in connection with a string of robberies.