A police boat on Saturday would be searching the Waikato River for Hamilton man Raymond Stirling.
His family just want the 84 year old to be found.
They, along with police, LandSAR volunteers and others have been searching extensively around Hamilton since Tuesday morning for Stirling, who suffers from mild dementia. He was last seen on Monday evening at his Halcione Close home in Flagstaff.
"We realise now that it's been a long time," his daughter Julie Caddigan said on Saturday morning. "He's not going to be in a good state if he is still alive. Otherwise, we still just want him back."
Caddigan last saw her father on Monday afternoon. They had just spent a week at the beach together.
She said he lived on his own - something he was quite adamant about - but had lots of assistance and family support.
"He's a lovely, lovely old man, but he's quite frail," she said.
"He loves his family, he's got children, grandchildren, great-grandchildren and we just want him back."
The family has a detailed map to show the area searched. All main landmarks have been scoured more than once: Hamilton Gardens, Hamilton Lake, Victoria Street, Chartwell Square, The Base, parks, green areas and neighbourhood backyards.
Searchers have also covered north Waikato - Huntly, Ngāruawāhia and Horotiu, where Stirling once lived and worked.
Approximately 40 LandSAR volunteers, including groups from Auckland, Tauranga and Rotorua, resumed the search just before 8am on Saturday.
Ngāruawhāhia volunteer firefighters were also searching their area.
Caddigan said another search of North Waikato was planned for Saturday.
"Just in case he's been given a ride somewhere - those are places of interest to him.
"Then we're just sending people to where we've already been. We've looked everywhere."
He's also been known to approach businesses looking for work in his previous profession as a butcher.
The family asked the local community through a Facebook group to help with the search.
Caddigan said a couple of hundred people turned up to help on Saturday morning.
"We just want to thank everybody for their help - amazing friends, co-workers, community, and people we don't even know.
"People have been out searching through the night, dropping off food ... It's been quite humbling."
No one saw Stirling leave his home, but he is believed to be wearing navy track pants and white sneakers with red stripes on the sides.
He also has a wound on the right side of his head from a recent operation.
If anyone has seen Stirling, contact police as soon as possible on 111.
Police also ask people in Hamilton to again check their backyards, sheds and other outbuildings in case Stirling has taken shelter there.