"There's been a bit of a delay because the aeroplane that they were going to take isn't able to fly," a Maritime New Zealand spokeswoman said this morning.
Instead, a helicopter took off before noon.
Mission Controller Neville Blakemore said last night a search off Northland was unsuccessful.
Maritime NZ said there were seven people on board the schooner Nina. Six were Americans (three men aged 17, 28 and 58, and three women aged 18, 60 and 73). A 35 year-old British man was also on board.
Navigator David Dyche is among those missing.
"To date, the RCCNZ has coordinated two extensive sea-based searches based on different scenarios, covering a combined area of 500,000 square nautical miles," the agency added.
Nina was built in 1928. Maritime NZ said the boat left Opua in the Bay of Islands on May 29. It had not been heard from since June 4, when it was about 370 nautical miles (685km) west-north-west of Cape Reinga.
Maritime NZ said anyone with information on the vessel should call the Rescue Coordination Centre on 0508 472 269 (0508 4 RCCNZ) from within New Zealand or +64 4 577 8030 if overseas. People at sea can contact the Maritime Operations Centre on VHF radio channel 16.
