A number of fuel containers have been seized by RGP officers at two locations over the weekend.
In the first incident at 2200hrs on Friday evening, officers stopped two vehicles on Waterport Road, which contained 5 fuel containers filled with 44 litres of fuel.
The two vehicles, one Spanish and one Gibraltarian, were seized together with the fuel.
A 34-year-old Spaniard was arrested on Suspicion of Carrying Dangerous Goods by Road.
An investigation is ongoing.
In a second incident on Saturday, a member of the public reported that someone was storing full containers on a residential roof top in the centre of town.
The four full fuel containers, which contained over 80 litres of fuel, were seized and officers from the uniformed Response Teams are now investigating who put them there.
An RGP spokesman said: “Fuel containers like this are taken out to sea on small RHIBs operating from Gibraltar’s beaches for the purpose of refuelling the larger RHIBs used by drug traffickers.
“We are thankful to the member of the public who alerted us to the fuel containers stored on a town centre roof top.
“As well as hindering organised crime in the drug trafficking trade, we’ve also removed the risk of fire or explosion in a residential area.
“Again, we ask anyone who observes a large quantity of these plastic containers to contact the RGP on 200 72500 or the Gibraltar Fire and Rescue Service on 200 79507. In an emergency, call 199.
“This information can be provided anonymously and there is no need to give your personal details.”