Volunteers from Marine Rescue Botany Port Hacking and Marine Rescue Middle Harbour are assisting a multi-agency search for a missing male swimmer at Little Bay Beach.
Marine Rescue NSW Inspector Joel Pemberton said vessels and crews were requested to assist by NSW Police Marine Area Command.
"Volunteer crews were assembled and rescue vessels Botany Hacking 30 and Middle Harbour 30 deployed at 12.30pm.
"Both Marine Rescue NSW vessels are working alongside Water Police, searching an area from Little Bay Beach to Cape Banks in the south.
"Sea conditions offshore are unfavourable, with a 3 to 5 metre south-east rolling swell.
"Marine Rescue NSW volunteers and vessels will continue searching until instructed otherwise by Marine Area Command," Inspector Pemberton said.
