In a social media post, the club said Tasmania's biosecurity was facing a new threat of "feral merch".

"This introduced pest has begun appearing on our shores in the form of fake Tasmania Devils hats, t-shirts, hoodies, sneakers, and even something called a "blanket hoodie," that has no place on this planet, let alone our island," they said.

A Facebook group called Tasmania Devils supporters page! warned its followers of a "really convincing" fake website selling Devils' hats.

"Heads up, this website has nothing to do with the Tasmania Football Club and there is no guarantee that you will ever receive the items if you hand over your hard earned money," the post said.

"For the record "tassiedevilsmerch.shop" is not an official supplier of Tasmania Devils Merchandise."

Currently, the only official merchandise available is the foundation jersey exclusive to foundation members, retailing at $99.95 on tasmaniafc.com.

According to the club, over 185,000 founding members have signed up since the club was officially launched in March.

The club assured more verified, authentic merchandise was on the way, including some made with Tasmanian suppliers.

"We promise that we hear you and we want to give you many more ways to show you support," they said.

"In the meantime, the release of Feral Merch into Tasmania requires your vigilance. The companies illegally producing and releasing this pest are using Facebook's technology to send their ads to anyone who follows this page.

"This means they are deliberately exploiting your enthusiasm and support for Tassie's first AFL team."

"Stay vigilant."