The 59-year-old North Albury man was allegedly caught mid-tour at Limmen Bight in the Gulf of Carpentaria.

Water police travelled to the area and said Mr Mason had been advertising charters in a shop and online.

He must front Darwin Local Court on November 15.

Police allege he had two unregistered fishing vessels.

Water Police Senior Constable Sean Stanley said illegal fishing ventures undercut licensed operations.

“Water police travelled to Limmen Bight, in the Gulf of Carpentaria, where the man was arrested in the process of conducting a tour,” he said.

“There are many costs involved to be a licensed fishing tour operator, including licence fees, registration and insurance.

“As a result, unlicensed operators may charge substantially less.

“The unsuspecting punter on board these operations think they’re getting a good deal, but if they are injured while on board the vessel, they are not covered by public liability insurance.”

Photos from the scene show six tents near the water in what appears to be a makeshift campsite.

Northern Territory Guided Fishing Industry Association executive Graeme Williams has seen unlicensed operators fined thousands. 

“It undercuts the licensed operations as they don’t have insurance, licences, first aid certificates, vessel surveys – they bypass all of that,” he said. 

"We work very hard to maintain that level playing field.”

Mr Mason did not want to comment as the matter was yet to go to court.