All Interislander sailings to and from Picton have been delayed as firefighters clean up a possible chemical spill at the South Island port.
Fire and Emergency told 1News that firefighters are working out what the chemical is.
They said a cordon was in place blocking entry to Port Marlborough while fire crews were working to examine and clean up the scene of the incident.
In a statement, Interislander executive general manager Walter Rushbrook said the cause of the incident is yet to be determined.
"All Interislander sailings to and from Picton have been delayed due to a possible chemical leak from a customer’s container in Picton yard," he said.
"The issue was detected in the yard around 2am as the container was about to be transferred to the ship.
"No one has been harmed and the cause of the incident is yet to be determined.
"Customers will be contacted directly to provide updates on their scheduled sailings."
Bluebridge has also been contacted for comment.