A full search began at 9am with seven police officers and 13 volunteers from Far North Search and Rescue scouring the bush around the hostel and Kerikeri Basin.
His daypack was found in bushes about 100m from the hostel but it was not clear if Samuel had discarded it or if it had been stolen.
His phone was still being used but police didn't know if he had it or someone else.
''We've also been making enquiries around town but we're relying heavily on the public for sightings, and we'd appreciate any assistance. Obviously there's a worried family back in the UK.''