It is understood a deadly island tiger snake seized by Tasmanian authorities had been illegally advertised for sale.
Tasmania's Environment Department said it was investigating the discovery of a tiger snake in a house in the Midlands town of Perth.
A member of the public reported it was being offered for sale, a departmental spokesman said in a statement.
Reptile Rescue Tasmania's Bruce Press said he was called out to the home where a woman reported the escape of two tiger snakes.
"The lady who let me in was very scared and jittery," he said.
It was believed two tiger snakes had been illegally taken by mutton-birders on one of the state's outer islands.
Mr Press captured one of the snakes, but there were fears the other remained on the loose.
"I was told there were two snakes in the premises; one was housed in a glass tank and the other one had vanished and they hadn't seen it for three days," Mr Press said.
"I searched the little unit, it wasn't in there. When the people were there they kept the door open to air the place out so it could be anywhere."
But an Environment Department spokesman said the department had no information to indicate a second snake was on the loose.
Island tiger snakes have twice the venom yield as Tasmanian tiger snakes — which are the fourth-most venomous in the world.
Mr Press said even a scratch from a fang could be lethal.
"If it breeds with the Tasmanian snakes, what it could potentially do is increase the venom yield of the Tasmanian tiger snakes because this one has a higher venom yield," he said.
"When you get a bite from a snake they don't normally give you much venom, with twice the amount of venom yield ... you could certainly die quicker from this snake."
