Once the dispute has been referred to a Trades Disputes Tribunal any lock-out, strike or irregular industrial action short of strike is unlawful. Any person who takes part in, incites or in any way encourages, persuades or influences any person to take part in, or otherwise act in furtherance of a lock-out, strike or irregular industrial action short of a strike that is unlawful under this section is guilty of an offence and is liable on conviction on indictment to a fine of five thousand dollars or to imprisonment for two years or both.