The boat was still in the area off Wainuiototo Bay searching with sonar, and the help of the police dive squad.
An RNZAF P3 Orion also searched around the northeast of Great Barrier Island, and the Trustpower Rescue Helicopter from Tauranga searched the coast between Waihi and Whitianga, Mr Blackmore said.
No distress beacon had been activated, but a search was launched after a friend of the pilot reported concern for his safety.
Reported sightings by members of the public indicated the plane might have continued flying in a northeasterly direction, Mr Blackmore said.
Further options for continuing the search would be evaluated overnight, he said.
Mr Kraidy, 53, is a listed shareholder and director of Hobby City. He lives in Mission Bay according to the electoral roll.
A Hobby City employee would not comment this morning but a source confirmed to APNZ that Mr Kraidy, whose Facebook page said he studied at Rhodes University in South Africa, was the missing pilot.
Mr Kraidy was reportedly a former South African air force pilot who had represented New Zealand at the Precision Flying World Championships.