Sydney - Three weekend fishermen recounted Saturday how they clung to a polystyrene box for 18 hours after their 5-metre boat sank off Australia's east coast.

One used his mobile phone to raise the alarm after their boat went down at nightfall off Queensland's Flat Island.

"We just kept each other company by talking and singing songs and, yeah, we had to push some people sometimes to stay awake," Tony Minns told Australia's AAP news agency.

They were spotted by a rescue helicopter 22 kilometres from where their boat sank and taken to Rockhampton hospital suffering from mild hypothermia. (dpa)