Teams are back on the ground in Wagin for the fifth day searching for 87-year-old James Ballantyne after efforts were scaled back overnight.

The elderly Wagin man, who is living with dementia, has not been seen since Saturday, and emergency services are still searching the townsite and surrounding bush and farmland, hoping to find him alive and well.

The search was scaled down on Tuesday night after tracker dogs joined teams of police and State Emergency Service personnel for the fourth day of the search.

Police and the SES have been on the ground in Wagin since Mr Ballantyne’s worried family reported him missing on Saturday evening.

The 87-year-old did not return from his walk on Leonora Street, and has not been seen now for more than 96 hours.

On Tuesday, 12 police and 20 SES units, four mounted police officers, a drone operator, and three privately hired tracker dogs were out searching for the elderly man.

Wagin police officer-in-charge Acting Sgt Edward Duffy said even more SES units travelled from the Perth metropolitan area on Wednesday to assist as the search continued for a fifth day, adding to the army of volunteers already determinedly searching for Mr Ballantyne.

The drones are also back up in the air for a fifth day, but the squad of mounted police officers were sent back to their duties in Perth on Wednesday morning after three days and two nights out searching.

Acting Sgt. Duffy said search teams would continue searching new areas and would also retrace their steps, making sure they had not missed anywhere Mr Ballantyne could be.

Police are urging the public to stay vigilant for Mr Ballantyne, to check their properties, and to check dash cam and CCTV footage between Saturday morning and Wednesday for any sightings of the 87-year-old.

Mr Ballantyne is now believed to have spent four nights in the bushland, where temperatures dropped to around 4C on Monday and Tuesday nights.

Mr Ballantyne is described as 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 sees Mr Ballantyne or who has information about his location is urged to contact police immediately on 131 444.