Police divers have joined a multi-agency search operation for a man believed to be inside a submerged car at the Royal National Park in Sydney’s south.

Emergency services were called to Audley Weir in the park about 1:15am, following reports a car had gone into the water with two people inside.

Emergency services were called to the weir about 1:15am Wednesday morning. (ABC News)

The 20-year-old male driver was able to get out of the vehicle, but his male passenger believed to be in his 20s became trapped.

It will be several hours before a police dive squad is able to assist, due to a team being requested for ongoing investigations into a fatal yacht rescue in South Ballina on the NSW far north coast.

The driver managed to escape the vehicle but his passenger became trapped. (ABC News)

However, NSW Police said the search delay also coincided with low night-time visibility, meaning the divers would not have been able to enter the water until first light this morning.

A second team has since been sent out.

Roads have been closed as investigations continue. (ABC News: Simon Amery)

Audley Road at Audley Weir is closed in both directions, and motorists are urged to avoid the area and use an alternative route. 

Police have established a crime scene and officers are investigating.