Two Japanese men have been arrested in the Australian city of Perth for allegedly attempting to smuggle 13 native lizards out of the country, Australia's customs authority said Thursday.

The two men, aged 51 and 28, were intercepted by Australian Border Force officials at Perth Airport on Wednesday while trying to board separate flights to Singapore and Kuala Lumpur, according to an ABF statement.

A total of 13 bobtail lizards were found inside a check-in suitcase belonging to the 51-year-old, the statement said, adding they were all found alive, but some appeared to be in poor health.

They were packed inside netted laundry bags, which were in turn wrapped in towels and placed inside two plastic containers with no food or water, the statement said.

[Australian Border Force]

Similar plastic containers were found inside the suitcase belonging to the younger man, and photos of the lizards were discovered on his mobile phone, it said.

"It will be alleged the men arrested yesterday are part of an international wildlife smuggling syndicate, and are linked to three other Japanese nationals charged with similar offenses in Sydney, Melbourne and Perth over the past six months," said Clint Sims, ABF superintendent of enforcement operations in Western Australia.

Both men were charged with attempting to export a regulated native specimen, while the 51-year-old was also charged with subjecting the lizards to cruel treatment.

[Australian Border Force]

The men were denied bail and were due to appear in the Perth Magistrates Court on Thursday.

Bobtail lizards are a slow-moving species of skink with a large triangular head and distinctive stumpy tail.

The native Australian species can fetch up to A$10,000 (around $7,000) each on the international black market.

The maximum penalty for wildlife trade offenses in Australia is 10 years' imprisonment and a fine of up to A$210,000 for individuals or up to A$1.05 million for corporations.