MAF Compliance Manager Canterbury/West Coast, Peter Hyde said the fisherman was likely to be charged.
A person who assisted in the sale of the rock lobster and some customers who purchased lobster may also face charges.
Mr Hyde said: "New Zealand's Quota Management System (QMS) requires accurate reporting of all commercially caught fish. Not reporting fish caught under the QMS is a serious offence.
"The type of offending alleged is rare in the commercial fishing industry. Thanks to the QMS, the stock of rock lobster around the Canterbury coast is in very good shape and we want to see it stay that way."
People should be suspicious if rock lobster is offered to them without any documentation at a price well below what you would pay at a fish retailer, MAF warned.
A single rock lobster offered for sale at between $20 and $30 is likely not to have been declared against quota and therefore illegal to be sold.
Mr Hyde urged members of the public who saw any unlawful activity, including suspected poaching or offering seafood for sale on the black market to phone 0800 4 POACHER (0800 476 224).
He said: "Calls are treated in strictest confidence and the information we receive helps us stamp out illegal fishing and helps ensure we have a sustainable fishery for future generations."