Dangerous swell is being probed as the cause of a boat capsizing where one man died and another was injured in northern NSW.
Two people were seen clinging to the upturned hull of a 6.5m boat at the north wall of the Tweed River Bar about 6am on Saturday.
Emergency crews launched a rescue operation including local and marine police, a rescue helicopter and lifesavers.
A 58-year-old man was pulled from the water and taken to Tweed Heads Hospital with minor injuries.
A 56-year-old man was winched from the ocean by a rescue helicopter and taken to nearby Duranbah Beach but was unable to be revived.
The men launched the boat from the Kennedy Drive boat ramp and were heading out across the bar when the boat capsized.
Acting Inspector Donna Tutt said police were investigating the cause of the accident but treacherous conditions were a likely contributing factor.
"It is very large dangerous swells at the moment," she said.
Police said neither man was wearing a life jacket.
"It's a tragic way to end the school holidays," Insp Tutt said.
"We urge all people to take care in the dangerous conditions and wear a life jacket."
The Tweed River Bar is popular for boating activities and commercial fishing, according to the NSW government.
Coastal bars are shallow, shifting sandbanks at entrances to rivers and coastal estuaries but authorities warn they can have strong currents and large breaking waves.
NSW authorities say crossing coastal bars can be very dangerous - even in calm conditions - as channels through the bars and waves can change frequently.
A report will be prepared for the coroner.
