Newly appointed police commissioner General Khehla Sitole has banned the posting on social media of pictures of suspects being arrested by police.

In an internal circular sent out on Monday last week, Sitole reprimanded those who have made such posts.

In October, Police Minister Fikile Mbalula was left red-faced after his Twitter post about the arrest of eight men allegedly linked to shootings in Marikana in the Western Cape backfired, as they were all later released without being charged.

The two-page circular, which Sowetan has seen, bans the publishing of pictures of suspects prior to their appearance in court.

The ban covers posts made on all social media platforms without written approval.

The circular was sent out to all divisional and regional commissioners, provincial commissioners, head of the Hawks and Mbalula through his chief of staff.

Mbalula, who has more than 1.1million Twitter followers, regularly uses his page to post pictures of police arrests and operations.

The minister's spokesman Vuyo Mhaga said the circular related to operational matters which the minister had nothing to do with.

"It's an operational matter which is something in the forte of the police commissioner," Mhaga said.

When asked if this circular would have an impact on how Mbalula handled his Twitter posts relating to police work going forward, Mhaga said the minister always ensured faces were blurred on his posts.

"I think it's not unlawful [to post pictures of suspects' arrests], but it's just not advisable ... the circular affects operations and our job is to do oversight," Mhaga said.

Sitole said there was "an increasing tendency to post photographs or videos of suspects on WhatsApp groups or unofficial social media platforms prior to their appearance in court.

"Such publication can prejudice an investigation or court processes and can render identification parades invalid," Sitole wrote.

Head of the justice and violence prevention programme at the Institute for Security Studies, Gareth Newham, said the circular was about enforcing "a well-established practice" as police had recently been encountering problems caused by the sharing and posting of suspects' images.

Newham said the October incident demonstrated problems caused when "politicians get carried away".

"The minister is not a trained police officer, he does not understand policing and sometimes encroaches on the operational sphere ... when he starts pretending to be a police officer, that's a problem," Newham said.

Mhaga defended Mbalula, citing this embarrassing incident as an exception.

"With the exception of that Cape Town matter ... [blurring pictures] is already what the minister has been doing."

However, Mbalula's Twitter account told a different story.

On Monday, he posted three pictures of a police operation, with one showing an arrest of a man wearing a white vest being pinned to the ground with a firearm pointed at him.

Oorhunta baseMpuma Koloni babanjwe banya #festiveOperation, (Eastern Cape crooks sh*t themselves when arrested #festiveOperation).

Even though the suspect's face wasn't clearly identifiable, it was still partly visible and the picture had not been blurred.