Police divers, volunteer climbers, sniffer dogs and a sophisticated new drone have all been deployed in the search for Belgian backpacker Theo Hayez in the past two days – but with no sign of him since he vanished three weeks ago, police have suspended the search for the weekend.

Authorities believe the key to locating him will be found in the steep, dense scrub and rugged cliffs surrounding the lighthouse at Cape Byron.

Police divers prepare to search water off Watego's Beach on Thursday. Credit:Danielle Smith

However, the intense efforts of dozens of SES, police and volunteer searchers in the past fortnight have failed to uncover a single trace of the 18-year-old last seen leaving a Byron Bay bar three Fridays ago.

Detective Inspector Matt Kehoe confirmed there would be "no physical search" for Theo over the weekend, as investigators review the week's efforts. Whether the search resumes on Monday will be determined that day.