It was found at the Yarralumla Wholesale Nursery on Friday has been "secured" by the ACT biosecurity team.

ACT conservator of flora and fauna Ian Walker suspected the toad had arrived in the territory in a shipment of nursery plants from Queensland the week earlier.

"We are confident that there is no risk to Canberra's environment because this one cane toad was inadvertently transported to Canberra on a truck," Mr Walker said.

"Teams from across government undertook an intensive search of the nursery and surrounding area over the weekend.

"No additional cane toads were located during these searches, indicating that this was an isolated incursion.

He said the community should still stay vigilant and report any suspected sightings.

"It is highly unlikely a cane toad population would establish this far south due to Canberra's cold winter climate, especially with the colder weather we experienced on Sunday," Mr Walker said.

"This incident was treated seriously, and through the diligence of the nursery staff in their reporting and the quick investigation and action from those involved in the response, any possibility of a population of cane toads persisting in the nursery has been removed."

It is not the first time cane toads have been found in Canberra. Two were detected in Campbell in 2018, and another was seen some months prior.

A cane toad was also discovered in the NSW southern Riverina last month, and experts suspected it too came on a truck from Queensland.

Cane toads are toxic at all stages of their life cycle from eggs to tadpoles to adults.

Their toxin is strong enough to kill most native animals that prey on frogs or toads and their eggs, such as birds, other frogs, reptiles and mammals, including some of our threatened species.

If you see what you think is a cane toad, you should not kill it as it most likely is a native frog.

Authorities say you should take a close-up photo and, wearing rubber gloves and eye protection, put it into a well-ventilated container with 1cm of water, then contact Access Canberra.