A 30-year-old woman has been found alive after an extensive overnight search off Fingal Head, ending a dramatic rescue after she failed to return from a swim at Dreamtime Beach.

Emergency services were called to Dreamtime Beach about 6.45pm on Monday after reports the woman had entered the water and disappeared.

Police, Marine Area Command, Queensland PolAir and the Westpac Rescue Helicopter searched the beach and surrounding waters into the night but were unable to find her. The search was suspended about 11pm before resuming at first light on Tuesday.

About 6.55am, the woman was located near a floating marker in the Tweed River, indicating she had apparently spent the night in the water.

Water Police, assisted by Police Negotiators, safely brought the woman aboard a police vessel before transporting her to Fingal Wharf.

She was assessed by NSW Ambulance paramedics at the wharf and taken to Tweed Valley Hospital for further assessment.

Police have not released any further details about the circumstances surrounding the incident.