Human remains found in search for missing South Australian man Joshua Clifton Demell

Human remains have been found during the search for a missing South Australian man who was last seen more than seven months ago.

Police this week renewed ground efforts to find the man, Joshua Clifton Demell, who disappeared in January near Port Augusta, saying they held "grave concerns for his safety".

A motorbike that the man was seen riding when he went missing was found abandoned in the area on January 24.

Far North region officer-in-charge, Superintendent Josh Heinze, said that human remains had been found earlier today, but that police could not yet confirm whether or not they belonged to the missing man.

"It is too early to confirm the identity of the human remains. They will be subject to forensic testing and I hope to have the results in the coming days," he said.

"As soon as the identity of the human remains is confirmed, police will provide a further update."

Police said they had been in contact with the family of the missing man — who was aged 39 when he disappeared — to advise that remains had been found.

They said they were not currently treating the matter as suspicious.

In the aftermath of the man's disappearance, emergency services launched what police described as a "significant ground and aerial search" over two weeks that involved a police helicopter and drones, as well as the State Emergency Service (SES).

Police said the Missing Persons Investigation Section conducted a review of that search and that the decision was made to return to the area this week to expand the effort in areas north of Port Augusta.

"On the day Joshua went missing, and during the initial search, Port Augusta was experiencing extreme heat with temperatures in the mid-40s," Superintendent Heinze said.

"The initial search extended over a number of weeks.

"The discovery [of the remains] was made outside of the initial search area but within the revised and expanded search area."

Superintendent Heinze said Joshua was last seen in Port Augusta West on January 23 and that his motorbike was found the following day around Yorkeys Crossing.

He said police were notified of his disappearance in the following week, and that the human remains were found "a number of kilometres" from the location of the motorbike.