Up to 70 rotting crocodile heads have been found in an old freezer dumped at a remote Australian town, police said Tuesday, with the culprits facing large fines and jail time if convicted of the killings.

Several teenagers made the grisly find behind a row of shops at Humpty Doo, 40 kilometres (25 miles) outside Darwin on Sunday and contacted authorities.

Police said at least 50 saltwater crocodile heads, and as many as 70, were stuffed inside.

"(We saw) a deep freezer in a sad state of affairs," senior wildlife ranger Tommy Nichols, who specialises in crocodile management, told the Australian Broadcasting Corporation.

"There was quite a bad smell and maggots around everywhere."

No one has been arrested but anyone convicted of killing protected wildlife faces a fine of up to Aus$76,500 (US$55,000) or five years in jail.

It was not clear why the heads had been severed but crocodile skins are highly prized and there is a thriving market.

Saltwater crocodiles, which can grow up to seven metres (23 feet) long and weigh more than a tonne, have become increasingly common in Australia's Northern Territory since they were declared a protected species in 1971.

Each year more than 500 are culled to protect the public and livestock, with the animals killing an average of two people a year.

Keeping them as pets is legal in the Northern Territory if they are under 60 centimetres.