A full-scale air and sea search is underway for a five-year-old boy missing off Pearl Beach on the NSW Central Coast.

Police say the boy was swept into the surf by a large wave about 1.50pm on Thursday.

A nearby restaurant owner said people had gathered around the beach and the mood was grim.

“We all feel sick to our stomach, we are worried about the poor parents,” said Melissa, from Pearls on the Beach restaurant.

“Everyone is feeling totally beside themselves.

“It’s quite rough out there.”

The Marine Area Command, Surf Life Saving Australia, Westpac Lifesaver helicopter and other agencies are looking for the child.