The number of reported rat sightings has increased this year, the Gibraltar government has said, citing milder winters and greater public awareness.
Officials urged residents to contact the Environmental Agency or licensed pest control firms rather than using poison themselves.
The agency said rats have adapted to live around humans and can be displaced by construction. It noted natural predators on the Rock include foxes, gulls, birds of prey and snakes.
The agency, which handles pest control in public areas and government facilities, said its first steps are blocking access and removing food and water sources.
Poison is used only as a last resort in bait boxes designed for rodents.