A fine of almost $401,000 is the first punishment dished out by the courts following the Commerce Commission's probe into steel mesh.

Timber King and NZ Steel Distributor have been fined for misleading customers and falsely claiming their steel mesh product was compliant for structural use in an earthquake zone.

The Commission has carried out a series of investigations into steel mesh following a complaint in August 2015.

While some companies received a warning or compliance advice, Brilliance Steel Limited is awaiting sentencing after pleading guilty to 20 charges, Steel and Tube Holdings Limited is awaiting sentencing after pleading guilty to 24 charges, and Euro Corporation is facing 59 charges.