The Melbourne Herald Sun reported Wednesday Per Johan Adolfsson, 28, tried to avoid detection by stuffing the snakes into socks and strapping them to his calves.
The cobras -- one almost 3-feet in length -- were dead when he was searched by Customs officers after he arrived from Thailand.
The cobra packaging was backed with cardboard to prevent bites, an indication that they died during the nine-hour flight. King cobras can grow up to 15-feet and are capable of killing an elephant.
The other four snakes are believed to be emerald tree boas and are in quarantine at Taronga Zoo.
Snake expert Tim Mensforth told the Sun Herald the smuggler would almost certainly have been trying to bring the snakes in alive to sell.
Mensforth said many exotic snakes were smuggled into Australia and this had led to an increase in imported diseases affecting native reptiles.