A total of 16,000 gallons of illegal fuel was on Friday found aboard two vessels docked at the Parika Stelling, East Bank Essequibo (EBE).
The bust was made by agents of the Guyana Energy Agency (GEA) at around 21:15hrs.
One of the vessels was captained by a 56-year-old man of Meten-Meer-Zorg, West Coast Demerara while the other was captained by a 44-year-old man of Greenwich Park, EBE.
At the time of the search and seizure of the vessels, one of the boats had a three-man crew comprising a 55-year-old man of Good Success, Wakenaam; a 54-year-old man of EBE; and a 20-year-old man of Meten-Meer-Zorg, WCD.
The five persons are presently in custody while the vessels are under police guard.
The GEA is investigating.