Blenheim diver Kevin Bailey is missing after failing to surface from an expedition to a 50-year-old shipwreck off the Timaru coast yesterday.
The crew of two helicopters and six boats combed the area above the wreck of the Holmglen until after dark, and the search will resume this morning.
Mr Bailey was in a group of divers who went down to the Holmglen, which is situated in about 60 metres of water.
Mr Bailey went missing on the ascent and the alarm was raised about 3pm.
Sea conditions were calm at the time and remained so for the search, which is being handled by the Rescue Co-ordination Centre in Wellington.
The helicopters had to refuel about 7.30pm and returned to the area, 36km south-east of Timaru, equipped with night vision equipment.
Six vessels, including PrimePort Timaru tugs, fishing boats and the Coastguard, were also involved in the search. All but one of the boats returned to shore when darkness fell.
The Holmglen is the only wreck dived off the South Canterbury coast, but at a depth of 63 metres it is restricted to divers using mixed gases.
The drift north of glacier flour from the Waitaki River means the visibility off the coast is usually limited to a few metres.
The Holmglen sank in heavy seas while en route from Oamaru to Timaru in November 1959.
The sinking of the small 485-ton coaster was a surprise because it was designed to supply the sub-Antarctic islands and was only five years old.
A radio message was received at Tairoa Head of the ship heeling hard to port, the accommodation area awash and crew attempting to launch a lifeboat. Then followed silence.
Several freighters, two navy vessels and 20 Oamaru and Timaru fishing boats were unable to find any survivors.
The 15 crew members died and only three bodies were ever recovered. An empty lifeboat was found three days later.
- The Timaru Herald
What is the best time for the Santa Parade in Blenheim?Related story: Blenheim 'buzzing' with festive cheer