(CNN)Seven people who were on a ferry that went missing in the South Pacific a week ago were rescued Sunday, New Zealand authorities say.
The seven were spotted by a New Zealand Air Force Orion patrol plane as they floated in the open sea about 300 kilometers (186 miles) southeast of Nauru island, said Sandra Ford, spokeswoman of the New Zealand Rescue Coordination Center.
The plane directed a nearby fishing vessel to pick up the survivors, she said.
The seven were among 50 people aboard the inter-island ferry MV Butiraoi, which left the island of Nonouti in Kiribati on January 18, bound for Betio in the Kiribati capital of South Tarawa, according to the release.
Ford said the survivors included three adult females, a 14-year-old girl, and three adult males. The oldest of the group was 34, she said.
The Rescue Coordination Center said Monday that a patrol vessel carrying medical personnel had been dispatched from Kiribati and would rendezvous with the fishing vessel, the FV Lomalo, on Tuesday.
Meanwhile, aircraft from Australia's Maritime Safety Agency and the US Coast Guard were being sent to join the search for the 43 people still missing, the rescue center said in a press release.
Authorities said the length of time since the ferry sank combined with ocean currents means the search area keeps expanding.
"We have full confidence in the aircraft and the radar equipment they have onboard. The searchers are guided by RCCNZ's drift modelling that takes into account wind and currents and targets their efforts to find any survivors," Greg Johnston, senior search and rescue officer, said in the release.
Ford described the area where the dinghy was found as "quite remote," and said other ships would take at least 24 hours to get there.
The ferry MV Butiraoi was on a 250-kilometer (155-mile) trip that was expected to take two days, according to New Zealand authorities.
When the 17-meter-long (56 feet) catamaran-style passenger ferry didn't arrive in Betio on January 20, the search began.
Ford said authorities were still trying to determine when the ferry sank, but she said it was thought to be early in its journey.
New Zealand's Rescue Coordination Center has been in charge of the search since Saturday, taking over from authorities in Fiji.
New Zealand is about 4,500 kilometers (3,425 miles) south of Kiribati.
Kiribati, with a population of 108,000, consists of 33 coral atolls about midway between Hawaii and Australia.
The CIA World Factbook points out that the country's main island of South Tarawa is one of the most densely populated places on Earth, akin to Hong Kong or Tokyo.