Prickly pear can form impenetrable walls of vegetation and cost millions of dollars to control once in the environment as it is extremely difficult to kill.

Its bristles and spines can cause serious injury to people and impale, infect, blind and even kill native animals, pets and livestock.

Eurobodalla Council's invasive species supervisor Paul Martin said the shire was lucky to have escaped a serious prickly pear infestation in recent years, and that's how we wanted it to stay.

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"Prickly pear is a declared plant under NSW biodiversity legislation for a reason," he said.

"Spring usually brings an increase in plant sales, so we're appealing to the public to be on the lookout for these cacti in markets and online."

Crime Stoppers, councils, Local Land Services and the NSW Department of Primary Industries have joined forces in a state-wide campaign to call for anyone who sees these plants for sale to report it.

Easy to propagate from cuttings, cacti are popular plants in household gardens, both indoors and outdoors.

But, the same rapid growth can cause widespread devastation in the natural environment.

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There are more than 27 species of prickly pear known to be in Australia.

Eve's needle, bunny ears, smooth tree pear and blind cactus are all types of prickly pear illegally traded in NSW, despite on-the-spot fines of $1,000 and penalties of up to $220,000.

Crime Stoppers has developed a fact sheet for more information, or if you're unsure, get in touch with council's invasive species team on 4474 1000.

You can also report sale of prickly pear anonymously to NSW Crime Stoppers on 1800 333 000 or online at https://nsw.crimestoppers.com.