A snake was found in a Sydney Airport women's toilet presumably after a reptile smuggler chickened out in transporting the slithering reptile by customs officers.

The snake, identified as a non-venomous 3-foot long green tree python native to South-East Asia, startled a bathroom attendant who was cleaning a ladies toilet on Sunday afternoon.

The smuggler remains at large and customs officials have no clue to his identity, but say the incident shows the effectiveness of tight security measures at the airport.

Customs NSW director David Collins says, "Reptile smuggling is not only a cruel practice but also poses a threat by introducing exotic diseases into Australia which could have a disastrous impact on native fauna."