The family of the deceased man would be notified by police and Victim Support.
His death has been referred to the coroner.
Lyttelton Port of Christchurch chief executive Peter Davie said the company was "extremely saddened" by today's fatality.
The death occurred at its container terminal, he said in a statement.
"All staff at LPC are deeply distressed by what has occurred and our thoughts are with the family and friends at this time," Mr Davie said.
"This tragic accident deeply affects everyone in our port community. We are focused on providing support services to the family and colleagues to help wherever possible."
All operations at the container terminal have been suspended until 7am tomorrow.
No further comment would be made while police and WorkSafe investigations were taking place, Mr Davie said.