Police inquiries are continuing and police say they cannot rule out any further arrests being made.
Detective Inspector Chris Barry earlier said five men, aged between 24 and 39, were arrested after police searched multiple addresses in Flat Bush and Papatoetoe this morning.
Singh was rushed into surgery after suffering critical injuries in the late-night attack.
Barry said he had been discharged from hospital and was continuing to recover from his injuries.
It was the second attack on Singh last year. He was also assaulted in Love Punjab Restaurant on his birthday in July.
Four of the accused men will next appear in the High Court at Auckland early next month.