Police launch new search in Ballarat area as part of Samantha ...

Victoria Police have recovered what appears to be a phone as they search a dam south of Ballarat as part of their investigation into the alleged murder of mother-of-three Samantha Murphy.

Ms Murphy, 51, was last seen alive on February 4 after she left her home for a morning run.

On Wednesday, police confirmed they had located "some items of interest" during their search.

"The area has been cordoned off and those items will now be forensically tested," a police spokespersons said.

"At this stage we are not providing further information about the items until that testing has been completed."

Vision from the scene shows a group of police officers gathering near what appears to be a dam at the edge of a property. 

An evidence marker was placed by an item which appeared to be a smartphone.

Later police could be seen with what looked like a metal detector scanning at the edge of the water. 

Police bagging an item found by the dam.(ABC News)

They asked members of the public not to attend the search.

Police said detectives from the Missing Persons Squad as well as a range of specialist resources and the Australian Federal Police were involved in today's search.

Ballarat woman Samantha Murphy was last seen on February 4.(Ballarat Courier: Adam Trafford)

They said Ms Murphy's family had also been advised of the search.

Patrick Orren Stephenson, 22, has been charged with murder over Ms Murphy's disappearance.

Police were seen using what appears to be a metal detector near the water's edge.(ABC News)

On Wednesday, police conducted a small-scale search along Slaughterhouse Road and Buninyong-Mt Mercer Road, a couple of kilometres south of Buninyong.

About 12 officers searched the area, scouring long grass and scrub on the roadsides and in the edges of paddocks.

An excavator was seen at the site where police are searching.(ABC News)

The dog squad were also involved and an excavator was seen on site, although the ABC understands the excavator was being used to help clear scrub, rather than digging in a designated spot.

Police have slowed traffic in the area, and have warned drivers to proceed with caution.

There have been numerous police searches in and around Ballarat since Ms Murphy's family sounded the alarm when she failed return home almost four months ago. 

Police launched an immediate search of the Canadian Forest, where she was known to run, but were unable to locate the mother of three. 

Extensive ground searches continued over the following week, but were scaled back on February 10 by police who confirmed her disappearance was being treated as suspicious.

About 12 officers scoured through grass and scrub by the roadside on Wednesday. (ABC Ballarat: Laura Mayers)

On February 23, a new search in the Mount Clear area took place which at the time police said was based on mobile phone data. 

The following day hundreds of people including community members and volunteers came together to search throughout the outskirts of Ballarat.

Police launched another search in April which was quickly wrapped up.  

It's understood Ms Murphy's phone, watch and headphones have not been recovered.