A leaking substance that caused the Picton ferry terminal to be closed has been identified as water, KiwiRail says.
Earlier today the Interislander ferry company said there was a corrosive chemical spill near the Picton terminal.
KiwiRail executive general manager Walter Rushbrook said until the substance was identified it had to be treated as potentially hazardous.
Fire and Emergency shift manager Jill Higgison said crews were called to the incident just after 2am on Thursday.
Fire trucks from Picton and Nelson were at the scene and there were no reports of injuries.
Earlier, Port Marlborough had to shut while the nature of the spill was being investigated. Interislander and Bluebridge ferry companies had also confirmed significant delays to services were likely as roads into the port were closed.
Interislander said the Kaiarahi service had been delayed and would now depart Picton in the early afternoon.
The spill originated from a leak in a passenger's hazardous goods container, the ferry company said.