Maritime NZ's Rescue Coordination Centre NZ (RCCNZ) began coordinating the search about 6.30pm yesterday after a brief and partial mayday call was received.
Senior Search and Rescue Officer Chris Henshaw said about 2pm on Thursday a vessel advised that it was the one that had broadcast the mayday call.
RCCNZ is standing down the search aircraft and vessel, Henshaw said.
After the mayday call, search and rescue officers believed there were two people on board and held serious concerns for their safety. But they had trouble locating the vessel.
The location was given to be near Waiheke. But a search to find the vessel found nothing - and officials think the yacht may have given an incorrect location.
This morning, it was believed that the yacht was around the east of the Coromandel Peninsula, off the coast of Pauanui.
The Navy ship HMNZS Te Kaha had been searching throughout the night; while two rescue helicopters from Auckland and Tauranga and a Coastguard boat were also involved.
The helicopters and Coastguard vessel were called back after searching for several hours due to heavy swells in the area.
Earlier, search and Rescue officer Tracy Brickles said a difficulty was the yacht didn't give any name of the vessel when it made the call last night.
"So we don't know who we're looking for ... It's extremely hard to search for them. ll they said was they're taking on water and they're sinking. We don't know even if they have sunk yet."
Last night's conditions were described as very poor and rough; with 3m swells and winds gusting up to 48km/h.
"When you're out on the water this summer, please take two means of communication and a distress beacon and safety gear - such as life jackets and flares that will help us to locate you," Brickles said.
