Missing Ballarat mum's disappearance deemed suspicious

Police Commissioner Shane Patton on Wednesday said the situation was unusual because police haven't been able to locate any trace or find any leads to Ms Murphy.

"When someone's been missing for this period of time, we have no trace, clearly there must be some suspicions there because we haven't been able to locate them," he said.

Dozens of volunteers and search crews have scoured areas of the Ballarat region including Buningyong, Eureka and Canadian state forest to no avail.

Missing Persons squad detectives went to Ballarat to investigate.

Police said on Saturday they had not identified any sinister circumstances surrounding Ms Murphy's disappearance but were very concerned about her wellbeing.

"Obviously Missing Persons is involved, it's suspicious, whether it means there's foul play involved or not, I don't know," Mr Patton said on Wednesday.

"But detectives investigating a matter where a woman's been missing for a significant period of time, call it unusual, call it suspicious, but it certainly is of significant concern to us."

Search crews have found no trace of Samantha Murphy, who disappeared after going for a run. (James Ross/AAP PHOTOS)

Detectives have been working with telecommunications technicians to track the route Ms Murphy travelled after confirming she had a smartwatch and phone on her.

Police are also sifting through CCTV footage submitted by the public to try to piece together Ms Murphy's final documented movements, saying a full-scale search will only resume if fresh information emerges.

"Missing Persons is tracing, stepping through timelines, looking at CCTV, examining many information reports we've received from the public," the commissioner said.

"So it's still early days but the concern is obviously there given that we've really got no leads."

The mother of three is described as mentally and physically fit and was training for an upcoming race by doing 15km runs.