Six adults and an unconscious baby were rescued on Sunday from a life raft in the Pacific Ocean after drifting for four days in the blazing sun without water.
The survivors had scrambled onto the small wooden dinghy after the ferry they were aboard sank, according to authorities.
New Zealand Defence Force Air Commodore Darryn Webb said the crew on a military Orion plane had used radar to locate the dinghy while searching for survivors.
He said the ferry had been carrying at least 50 people while travelling between two islands in the remote nation of Kiribati.
Webb said there had been no sign of any other survivors. He said it was not yet clear what caused the ferry to sink.
The plane dropped supplies to the survivors including food, water and a radio, Webb said. The survivors used the radio to tell rescuers they had managed to get off the ferry when it capsized and climb aboard the dinghy, he said.
Webb said the survivors had very little time to react and found themselves adrift without water or an engine. He said they did have a blanket or tarpaulin which they may have been able to use to get some relief from the sun.
Webb said a fishing boat had changed its course and picked up the survivors on Sunday afternoon. He said the dinghy was drifting more than 112 miles from the nearest major island when it was found.
"Our heart goes out to the baby and to all those remaining of the 50-plus people," he said.
While thankful the life raft was found, Webb said it was also heartbreaking the ferry had sunk and the others were still missing. He said there was a lot of debris near the dinghy, which may have been from the ferry.
Searchers planned to regroup and interview the survivors before deciding whether to continue the search, he added.
Questions remain as to why it took Kiribati authorities so long to tell New Zealand officials the ferry was missing. Webb said a Kiribati plane had earlier searched for the ferry but didn’t have sophisticated radar equipment.
Named the MV Butiraoi, the 57-foot wooden catamaran left Nonouti Island bound for South Tarawa on January 18, according to authorities. The journey was supposed to take two days. New Zealand rescuers say they were not told about the missing boat until Friday, eight days after the ferry had left.
Senior Search and Rescue Officer John Ashby said they had been told the ferry underwent repairs to its propeller shaft just before leaving, which may have contributed to navigation problems.
Kiribati is a remote, impoverished nation of 33 atolls that is home to about 108,000 people.