Nelson's controversial horse and cart man is recovering from chemical burns to his mouth and throat following an attack.
Police are investigating the incident which happened outside the entrance to the Nelson City Council around 6:45am.
Lewis Stanton, also known as Hone Ma Heke, was assaulted while he was sleeping outside the city's council building this morning.
A nearby worker says he looked in a bad way and asked him to call an ambulance.
Constable Nick Kempthorne called the attack "cowardly" and said police were taking the attack extremely seriously.
They are still trying to confirm what the substance is.
They want to speak to anyone with information about the attack or who was near the Trafalgar St and Halifax St intersection around the time of the attack.
Anyone who has CCTV footage from the nearby area is also asked to come forward.
Mr Stanton had been in a long-running court battle over unpaid fines for parking his horse and cart in central Nelson.
Those with information can call Const Kempthorne on (03) 546 3840 or anonymously via Crimestoppers on 0800 555 111.
3 News / RadioLIVE