WELLINGTON, New Zealand — Authorities on Friday called off an aerial search for survivors of a ferry that sank last month while sailing between two islands in the remote Pacific nation of Kiribati.

An estimated 81 people are missing and presumed dead. Seven survivors were rescued from a small wooden dinghy on Sunday, after a military plane from New Zealand used radar to locate the craft.

Kiribati government spokesman Tearinibeia Enoo-Teabo told The Associated Press this week that maritime authorities had ordered the MV Butiraoi ferry not to take any passengers because it had earlier sustained serious damage to its navigational system, rudders and hull.

He said the government is investigating why the ferry left despite the orders.

It remains unclear whether the ferry had undertaken any repairs before it left.

Authorities say they believe the 17.5-meter (57-foot) wooden catamaran was carrying 88 passengers and crew when it departed Nonouti Island bound for South Tarawa on Jan. 18. They believe it sank that same day.

Kiribati authorities say the journey was supposed to take two days but it was a week before they learned the vessel was missing. That delay is also likely to be part of the investigation.

Four search planes from New Zealand, Australia and the United States scoured the ocean until Kiribati’s government decided to suspend the aerial search. It plans to continue searching with local boats.

The survivors told rescuers that they had drifted for days without water. They were picked up by a fishing boat and later transferred to a Kiribati patrol boat with a doctor aboard.

Authorities said the three men, three women and 14-year-old girl were in reasonable health and were due back on land Friday.

Kiribati is made up of 33 atolls that are home to about 108,000 people.