The search for the missing 87-year-old man who lives with dementia has entered its third day after crews failed to locate him overnight.

James Ballantyne has not been seen since 10.30am on Saturday morning, when he left his home to go for a walk and failed to return.

He has now been missing for almost 48 hours and is believed to be moving on foot, with a huge team of SES, police and community members resuming their land and air search in the area around Wagin on Monday.

Search operations honed in on an area near Lake Parkeyerring, about 7km south of Wagin, following a sighting from a passing motorist and another area north between Wagin and Narrogin.

Mr Ballantyne’s worried family contacted police on Saturday evening when he never returned from his walk on Leonora Street, with a search commencing that evening and continuing through the night, including a nighttime drone operator and ground sweeps.

Police sent out an emergency alert asking residents in the vicinity to check sheds and outbuildings in case Mr Ballantyne had sought shelter.

Searches resumed on a larger scale at 7am on Sunday morning, with police aircraft, SES teams, drones, members of the community and Mr Ballantyne’s family scouring the area and conducting thorough grid searches.

Operations were scaled down overnight for the safety of the officers and volunteer crew before resuming at full force on Monday.

Mr Ballantyne is now believed to have spent two nights in the bushland, where temperatures dropped to around eight to nine degrees overnight.

On Sunday, Wagin police officer-in-charge Acting Sergeant Edward Duffy said crews were focusing their sweeps on an area near Parkeyerring Lake, about 7km south of Wagin, after a driver reported a sighting in that area.

“In the first first 12 to 24 hours, we had multiple reports (of Mr Ballantyne), a lot of them from members of the public who saw him during the day, which was yesterday on Saturday,” he said.

“Unfortunately, the only report we’ve had today was from a passing motorist, and they’ve identified the clothing that he was wearing, and the description of him and for the last couple of hours, we’ve been focusing our efforts on that report.”

About 55 police officers, SES volunteers, and community members have been involved in the search for Mr Ballantyne, who has lived in the small Wheatbelt town for about 20 years.

Acting Sgt Duffy said calculations on Mr Ballantynes average walking speed put him at about 5 to 10km out of the townsite, as he may have become confused and unable to find his way home.

“He has an onset of dementia, which varies, and it’s something you can’t really quantify,” he said.

“Some days he’s really good. Speaking to the family the day before, he was in very good spirits, and he is fit and quite healthy for his age.

“He chops wood every day, and he used to really love walking his dog Rory, and now Rory’s a bit over the age to go walking, but James, or they call him Jim, still goes out walking.

“He’s still mobile. We still believe he’s able to move, and then once again tomorrow morning at 6am we will do another quick briefing, and by 7am we’ll have SES and police resources back out on the road.

“The horses are staying overnight with their operators, and also the emergency command post will be operating tomorrow morning as well — we’ll just continue operations to search for him, find him and bring him home.”

Mr Ballantyne is described as being 183cm tall, of medium build and with short greying hair.

He was last seen wearing a navy-blue jumper and khaki-tan pants.

Anyone who sights Mr Ballantyne or who has information about his location is urged to contact police immediately on 131 444.