Australian Border Force (AFB) police said Sunday searchers were looking for between 20 to 30 suspected boat migrants believed to be hiding in Queensland's Daintree National Park, whose management maintains constant crocodile warnings.

Read more: Commonwealth Games athletes apply for asylum

The deserted fishing boat was found half-submerged and leaking fuel off the park - 772 square kilometers (298 square miles) of coastal mangrove and rain forest. On its seaward side lies the Great Barrier Reef, also known for its hammerhead sharks.

People seen 'running off into the bush'

Australian Channel Seven television claimed that those found ashore were Indonesian, while The Australian newspaper speculated they might be Vietnamese.

ABC broadcasting quoted a local tourism operator, David Paterson, as saying: "Boaties were saying over the radio, it was adrift and before that people were seen leaving it and running off into the bush."

"It's really quite treacherous to be in crocodile habitat in the Daintree, in the mangroves and in the rain forest," said Julia Leu, mayor of the local Douglas Shire Council.

First boat migrant entry in four years?

If confirmed that the boat carried asylum-seekers, it would be the first such entry in four years into Australian coastal waters under Canberra's controversial policy of turning back migrants on the open ocean or sending them to remote Pacific camps.

Brisbane's Courier Mail newspaper showed photos of border police standing around a group seated on an isolated Daintree National Park beach, commenting some were "well-dressed" with "their luggage at their feet."

A police dog squad had been deployed to find the missing occupants, it added.

Hard-liner likely back in office

The boat's arrival coincides with turmoil in Australian politics.

Queensland parliamentarian Peter Dutton looks set to retain his Home Affairs portfolio with his "stop the boats" slogan after initiating last week's federal Cabinet coup that saw Malcolm Turnbull replaced by Scott Morrison as prime minister.

Australia's Department of Foreign Affairs said police were "responding to what we believe to be an illegal fishing vessel" while the Courier asked "how the foreign fishing boat slipped in under the radar" of Australian coastguard patrols.

Daintree park's Tribulation Point is where in 1770 explorer James Cook's ship Endeavour briefly ran aground.  

ipj/ng (AFP, dpa)