Sanford has pleaded guilty to charges relating to an oil spill in Port Timaru.
Counsel for the fisheries company appeared briefly at a hearing in Christchurch District Court on Wednesday morning.
The Canterbury Regional Council charged that a Sanford boats spilled more than 4000 litres of oil into the harbour on 2 May last year.
The council took more than a week to clean up the spill at a cost of than $30,000.
Sanford initially pleaded not guilty to the charge.
The sentencing will be held in April.