Port Otago marine and infrastructure manager Sean Bolt said the man was "struck by a container" about 11.30am yesterday.
He was then taken off the ship using a man-cage slung under a container crane, to a waiting ambulance.
Mr Bolt said although the man was able to walk, he was taken to Dunedin Hospital for a checkup, in case there were any internal injuries. St John described the injuries as "moderate". Mr Bolt was unable to provide further details of the incident, as it was now under investigation by Maritime New Zealand, and WorkSafe had been notified.
Loading of Maersk Inverness was stopped following the accident, and was expected to resume about 7am today.
The ship is due to depart about noon today, once loading was completed, which meant it would be about 24 hours behind schedule.
Maritime New Zealand investigating staff were sent to Port Chalmers late yesterday.
