Four men set off on an overnight fishing trip from Mission Beach on Friday before their vessel experienced engine trouble, and took on water the next morning before sinking.

Police believe the men attempted to swim to an island nearby after failing to activate the boat's Emergency Position Indicating Radio Beacon.

A 36-year-old Tongan national was found at 4.30pm on Sunday clinging to a buoy off the Queensland coast.

He was rescued during the aerial search and remains in Innisfail Hospital suffering from exposure and hypothermia.

The three missing men are a 24-year-old local who owns the boat and two Vanuatu nationals, aged 26 and 31.

The two Vanuatuans are in Australia on work visas and are fruit pickers in the region.

Police located an item of interest from the vessel on Tuesday and will speak to family members before releasing that information.

Local SES, helicopters, fixed wing aircraft, quad bikes and Volunteer Marine Rescue have all been deployed in the search thus far.

Acting Inspector Brett Jenkins said given the time since the men went missing, the most efficient use of police resources is to base them on the coast and shorelines and conduct a thorough search of those areas.

"The information that I have is that we will start to scale back aerial and sea assets, but we will increase our land based assets and focus more on the coastlines," he said.

"We'll continue our land-bases searches until we are satisfied that we've sufficiently covered the search area."

Australian Associated Press