SA Police spokesman Lieutenant General Solomon Makgale said the five men, all in their 20s, were arrested on Wednesday.
The latest arrests brings to six the total number of suspects taken into police custody over the shooting.
Mthembu was attacked while withdrawing money from an ATM in Mandela Street, Emalahleni, on 19 October. He was approached by an armed man and several others who demanded that he withdraw all his money from his account.
A scuffle ensued and Mthembu was shot. The bullet grazed his cheek and hit him in the shoulder.
The first suspect to be arrested, Joseph Makhosonke, has already appeared in court.
He will join the five other accused in the Witbank Magistrate’s Court on Friday where all will face charges of attempted murder and armed robbery.
The African National Congress welcomed the arrests.
“The ANC commends the swift and unrelentless [sic] work by our law enforcement agencies, working in partnership with Absa and the use of the surveillance equipment, in the pursuit of this and other criminal matters in our country,” spokesman Zizi Kodwa said in a statement.
After a 10-day hospital stay, Mthembu was discharged last week. He was booked off work until the end of November.