The only centre in Australia milking snakes and spiders to make anti-venom has issued an urgent appeal for sightings of death adders.

Supplies of death adder venom are running low and lives will be at risk if more snakes are not found, the Australian Reptile Park's Mary Rayner told the BBC's Angie Knox.

The centre, just outside Sydney, is asking members of the public to report sightings of the snake so that a licensed snake catcher can capture it and bring it to the park for milking.

Australia is home to the world's six most poisonous snake species and produces anti-venom for itself and several countries in the region.

Sole supplier

The snakes the park keeps for venom milking were killed in a fire in 2000.

"It's taken us a while to actually build numbers up with most of the snakes but we just cannot do it with the death adders and that's why we put this appeal out," Ms Rayner said.

The park is the sole supplier of venom to the Commonwealth Serum Laboratories (CSL) in Melbourne.

"It is life threatening. If the CSL don't have enough venom to produce anti-venom from, then people are going to die," she said.

Medical advances

Death adders are found across most of Australia.

Fifty to 100 years ago, around half their bites were fatal, but with the development of anti-venoms and improvements in medical treatment, deaths are now very rare.

The snake's venom causes paralysis.

"Eventually, the way it's going to kill you is by respiratory failure and heart failure," said Ms Rayner's colleague Craig Adams-Marr.