Four spiders - with venom that can kill children and the elderly with a single painful bite - were found in Grafton maximum security prison in New South Wales state on Feb. 15, documents released Tuesday by state opposition lawmakers said.

Prison authorities suspect inmates found the spiders, which are common in Australia, in the prison nursery. They bred the spiders in jars, milked them of venom which they diluted with water before injecting, opposition Liberal Party justice spokesman Andrew Humpherson said.

"It just shows how comfortable they are - actually accessing and in this case breeding their own source of venom; their own source of drugs," Humpherson told reporters, in an attack on the Labor-led state government's law and order policies.

The Liberals accessed the state prison records under freedom of information laws.

The records also showed that a 16-inch marijuana plant was found growing in another prison in February.