Three people have died after a yacht and a rescue boat sent to help it got into trouble in heavy conditions off the northern NSW coast.

A member of the republic called emergency services about 6.15pm to report a yacht having difficulties off the South Ballina break wall.

Police said Marine Rescue NSW crew responded but their boat rolled while crossing the Ballina bar in “heavy conditions” and it was believed the yacht sank.

Search and rescue team look for missing surfer DarcyPolice said Marine Rescue NSW crew responded but their boat rolled while crossing the Ballina bar. (FILE) (Marine Rescue NSW)

Police said three people died and four made it to shore but it was unclear how many had been on the yacht.

Water police and general duties officers are on scene as Marine Area Command coordinates a search helped by the AMSAR Challenger jet and Westpac Rescue Helicopter from Lismore.

Paramedics were checking the four people who made it to shore but police said none of them were believed to have life-threatening injuries.

More to come.