There are "grave concerns" for the safety of a British man and his six crew-mates aboard a sailing ship that has gone missing en route from New Zealand to Australia, authorities have said.
The 70-foot (21m) schooner Nina and her crew - the 35-year-old Briton and six Americans - has not been heard from for more than three weeks, Maritime New Zealand said.
Two search and rescue missions by an aircraft covering almost half-a-million square miles of the Tasman Sea, which the 75-year-old vessel was trying to cross en route to Newcastle, New South Wales, have failed to find any sign of the ship or her crew.
Local conditions in the 1,400-mile-wide sea separating Australia and New Zealand were poor at the time Nina was last heard from on June 4, according to Kevin Banaghan, spokesman for the Rescue Co-ordination Centre New Zealand (RCCNZ).
"Unfortunately, no sign of the vessel has been found," he said. "Our records show that conditions at the last known position for the vessel, on 4 June, were very rough, with winds of 80kph (50mph), gusting to 110kph (68mph), and swells of up to 8 metres (26 feet).
"We do hold grave concerns for the Nina and her crew but remain hopeful of a positive outcome."
The ship, crewed by the Briton, three American men aged 17, 28 and 58 and American women aged 18, 60 and 73, left Opua on New Zealand's North Island on 29 May. When last heard from six days later she was about 370 nautical miles west-north-west of the country's most northerly point.
The New Zealand authorities started attempting to make communications contact with the boat on June 14, after being alerted by the families of those on board, also alerting other ships in the area to look out for her.
On June 25 and 26 a New Zealand Air Force Orion P3 search aircraft scoured the area but without success.
The RCCNZ said the ship was equipped with a satellite phone, a spot device which allows regular tracking signals to be sent manually, and an emergency beacon. The emergency beacon has not been activated, it said.