a vessel said it had broadcast the mayday.
Both occupants on board were safe.
Coastguard later told the Herald that the distress call was made after the boat battled 8m swells.
Search and rescue officers believed at the time two people were on board and were seriously concerned about their safety, but they had trouble finding the vessel.
The location was given as near Waiheke. But a search found nothing - and officials think the yacht may have given an incorrect location.
This morning it was believed the yacht was around the east of the Coromandel Peninsula, off the coast of Pauanui.
The Navy's HMNZS Te Kaha searched for the missing boat throughout the night. Two rescue helicopters, from Auckland and Tauranga, and a Coastguard boat were
also involved.
The helicopters and Coastguard vessel were called back because of heavy swells.
'All they said was they're taking on water and sinking'
Search and Rescue officer Tracy Brickles said earlier the search was more difficult because the yacht didn't give its name in the call.
"So we don't know who we're looking for. It's extremely hard to search for them.
"All 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 lifejackets and flares that will help us to locate you," Brickles said.
Don't hesistate to call
A Maritime NZ staff member expected to meet Tribe's skipper tomorrow to find out what happened and what lessons can be learned.
Henshaw said anyone on the water who believes their life is in danger should not hesitate to makea mayday call or activate a distress beacon as delay can be fatal.
"If the situation changes for the better, then cancel the mayday," Henshaw said.
"You will be thanked for the cancellation – no one will be critical or angry.
"If you activated a beacon and are no longer in danger, then make sure you leave the beacon on until you are contacted by rescuers. If you turn it off, we have the position you were at but no way of knowing if you have moved or what has happened.
"Our advice to everyone going boating is take two waterproof ways to call for help.
"A VHF radio and distress beacon are the best.
"Close to shore, a cellphone in a waterproof bag can be one way to call for help."
