Boaties are being asked to avoid an area in the Marlborough Sounds where the navy is using underwater sonar units to search for missing Blenheim man Craig Partridge.
The 45-year-old Omaka Valley winegrower fell off a launch in the Endeavour Inlet area of Queen Charlotte Sound early on Tuesday morning.
The navy's mine counter measures team are asking boaties to avoid the area in Endeavour Inlet while they carry out the underwater search.
Navy members are working with divers onboard the police launch Lady Elizabeth IV.
A police spokeswoman said private boats were also searching for Mr Partridge in the Endeavour Inlet area.
''It is important for people to know if they are choosing to go out and be helpful that there is an exclusion zone,'' she said.
The sonar search area will be marked by buoys.
Divers are continuing to search along the shoreline for Mr Partridge today.
The navy joined the search for Mr Partridge yesterday, using advanced equipment to get an accurate picture of the seabed within co-ordinates in the search area.
Police said on Wednesday they had recovered a jacket belonging to Mr Partridge in the search area.
Mr Partridge is believed to have been with his daughter and her partner on a commercial fishing boat when he disappeared overboard in Endeavour Inlet about 2am on Tuesday.
They had been at Furneaux Lodge during the night. Lodge owner Geoff Faulkner said the trio left the lodge about midnight to go back to a bach at Marine Head, near the entrance to Endeavour Inlet.
It is understood Mr Partridge was not wearing a life jacket when he fell overboard. It is believed his daughter sent out a mayday call about 2.50am, saying a person had been lost overboard.
- © Fairfax NZ News