The person in hospital is understood to be in a stable condition.
Auckland Tramways Union president Gary Froggatt confirmed the victim was a bus driver and one of their members.
Froggatt said the driver, who is between 40 and 50 years old, got into an altercation with a passenger while driving down White Swan Rd.
“Unfortunately he left his bus seat and followed the passenger on to the footpath, where he was stabbed twice, and was taken to hospital,” Froggatt said.
He says the knife scraped the driver’s lungs.
“It wasn’t as serious as we originally thought, however he was kept in hospital overnight,” Froggatt said.