It's been a week today since Colin McCormick went missing on Lake Rotoiti - and his family are preparing themselves for the possibility his body may never be found.

He dropped below the surface of the lake just a short distance from his partner and his 9-year-old son, who were unable to manoeuvre the boat to his aid.

The search for the 48-year-old, who is presumed drowned, has moved into a new phase with the navy completing its sonar search and the National Police Dive Squad having left the lake.

Surface checks of the lake are now being conducted by Search and Rescue, Harbourmaster and the Coastguard.


Colin's brother Gavin McCormick told the Rotorua Daily Post today the family was taking each day as it came and were "incredibly humbled" by the effort, time and determination of searchers.

"They are amazing people that have given everything to recover my brother's body," he said.

"We've known from Wednesday evening that it was not going to be a rescue, it was going to be a recovery but the tireless support and ownership from police, the navy, Coastguard, Search and Rescue and Harbourmaster has been absolutely exceptional.

"We watched every day as the police divers went out and didn't come back until dark, absolutely drained.

"They have really given it their all and are risking their own lives to recover him, we want to make sure they know we are so thankful for that."

Gavin said locals in the area, including local iwi, had also been "extraordinary".

"Everybody has been so genuine and sincere with one family taking us in and taking amazing care of everyone. There are some very special people in this area.

"We've had different kaumatua coming to see us every day to check if we needed anything."


He said while they still held out hope of his brother's body being recovered, the family was "prepared for either outcome".

"Colin's partner is writing the report for the coroner's office now so that's the next formal step to take.

"For us it is about understanding what went wrong, especially because he was such a strong swimmer - he loved the water more than any of us. If we don't get his body back, it means we don't get an autopsy to see if there was an underlying condition.

"Everybody deals with grief differently but we are a very tight family.

"No matter the outcome, there will be no doubt in anybody's mind that the people who have been searching for my brother have gone well above and beyond the family's expectations."

Colin went missing after jumping off his boat to retrieve his hat that had blown away.

His lifejacket came off in the process and drifted out of reach. His partner and son, who were on the boat, did not know how to operate the vessel to get to him.

A gust of wind pushed the boat, quickly moving it further away. His partner tried to throw him a rope but it wouldn't reach. Colin was treading water for a short time before going under.

Rotorua constable Colin Fraser from Search and Rescue said the search requirements were being assessed on a day-by-day basis, in consultation with the family.

Interpine Forestry Ltd has loaned its commercial drone with polarised camera, which is being used every morning and evening to scope and identify areas in the lake.

The rahui - a form of tapu - previously placed on part of the lake has been lifted.