Two fishers are likely to face prosecution after being caught with 261 flounder at Caroline Bay in Timaru.
The daily limit is 30 per person.
Ministry for Primary Industries' compliance director Dean Baigent said serious fisheries charges were likely to be laid.
The ministry was generally happy with the level of compliance for recreational fishers around the country over the three week holiday period, he said.
However, some shellfish gatherers were the exception, including people in the Auckland area, who were taking more than the 50 cockles allowed per day, and paua gatherers in pockets of the east coast from Gisborne to Canterbury.