Northern NSW: Boating tragedy with one man dead and another rescued after their craft capsized crossing Tweed River coastal bar

A man is dead and another has been rescued after their boat capsized while crossing a coastal bar in northern NSW.

Two people were seen clinging to the upturned hull of a 6.5metre boat at the north wall of the Tweed River Bar about 6am on Saturday.

Emergency crews launched a multi-body rescue operation including local and marine police, a rescue helicopter and lifesavers.

One man was pulled from the water and taken to Tweed Heads Hospital for precautionary checks.

A second man was winched from the ocean by a rescue helicopter and taken to nearby Duranbah Beach but was unable to be revived.

He is yet to be formally identified.

The men launched the boat from the Kennedy Drive boat ramp and were heading out across the bar when the boat capsized.

'Initial inquiries indicate neither man was wearing a life jacket,' a NSW Police spokesperson said.

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.

Investigations into the incident are continuing and a report will be prepared for the coroner.