The Ministry for Primary industries believes two recent cases of illegal paua gathering in Northland is only the tip of the iceberg.

The offending which occurred in the Whananaki area, included two men who were found with 164 paua, despite the limit being 10, all undersize.

MPI Compliance Manager, Stephen Rudsdale believes most offending is going undetected.

"We believe there is a lot of paua poaching going on that we unfortunately can't apprehend everybody."