The daughter of missing Ballarat woman Samantha Murphy has not given up hope her mother will be found alive, and has made a tearful plea for help finding her.

The 51-year-old Victorian’s distressed family held an emotional press conference on Thursday, talking though tears as they spoke about the mother of three.

The missing trail-runner’s eldest daughter Jess cried and wiped away a stream of tears as she made a public plea for her mother to “come home”.

“Mum we love you so much and we miss you and we need you at home with us; please come home soon,” she said.

“I can’t wait to see you and to give you the biggest hug when I do, and to tell you off for giving us so much stress.”

Jess said her mother was a “really strong woman” and  “far too determined to give up this fight”.

“I know she’s out there somewhere, so if you can please continue to search for her to give us something to work with, we’d really appreciate it,” she said.

Jess was comforted by her father, Murphy’s husband Michael, who put his arm on his daughter. He appealed to anyone with information that could help to come forward, and for the community to continue the search.

“People just don’t vanish into thin air, someone’s got to know something,” he said.

“Call the police, them let them, you know it will give us a bit of peace of mind, it will give some hope.”

SES personnel search farmland in Ballarat. Photo: AAP

He pleaded for people to respect the family’s privacy amid the growing public interest in the baffling case, and thanked the local community for their support.

“The generosity throughout the community has been unbelievable,” he said.

“If we went in to accept all the food that would want to be cooked for us or anything like that, we wouldn’t have to buy it or go to the supermarket for 12 months.

“Thank you very much to everybody. We really, really do appreciate everything that everyone’s doing.”

Samantha Murphy disappeared five days ago after going for a run. She  was last seen leaving her Eureka Street home at Ballarat East about 7am on Sunday.

Police said her disappearance was out of character and they were concerned for her welfare after temperatures reached 36 degrees.

Tweet from @VictoriaPolice

‘No suspicious circumstances’

On Thursday, Ballarat police acting inspector Lisa McDougall said “no suspicious circumstances” had been identified.

But CCTV footage did show a person running in the opposite direction of the search area.

“That CCTV footage is being examined and analysed to see if there is relevance,” McDougall said.

She said investigators were “keeping an open mind and considering all possibilities”.

“We’re being extremely thorough and methodical with that investigation,” she said.

“The search is ongoing and we’re throwing all those resources at it in the hope that we find Samantha and get some answers for her family who are obviously concerned.

“There are no suspicious circumstances that we’ve identified at this stage.”

Crews have searched in the Canadian Forest area since Monday. On Wednesday, they shifted their focus to the Ballarat suburb of Mount Helen, east of Geelong Road, while more searchers canvassed paddocks in nearby Warrenheip.

A friend of Murphy said the 51-year-old was an extremely dedicated mum, and described the situation as an “absolute nightmare rollercoaster”.

“I’m beside myself and I could not even imagine how [the family] are at the moment or how they’re even coping,” Virginia O’Loughlan told Seven’s Sunrise.

She said Murphy had recently returned to running and was training for a race.

“Sam is extremely fit. Sam is the most strong woman I know and I’m not just talking about mind, I’m also talking about body,” O’Loughlan said.

“Sam is a fierce woman who will be doing whatever she can at the moment to make sure that she’s reunited with her family.”

Samantha Murphy’s disappearance is out of character. Photo: AAP

Murphy’s friend praised the community for its efforts in searching for her, saying she was a sensible person who would have stuck to the tracks.

“We need as many people as we can out there, whether it be in cars, on foot, horseback, motorbike, just continually looking and just trying to work out where Sam would be,” she said.

Police on Wednesday released more CCTV footage they said showed Murphy running at 7.16am on Sunday near her home, heading towards Yankee Flat Road.

Residents in the area have been asked to review any CCTV from 7-11am on Sunday.

Crews found some items on Wednesday but they were not believed to be related to Murphy’s whereabouts.

Murphy is Caucasian, about 173 centimetres tall with a slim build and shoulder-length blonde hair.

She was last seen wearing black half-length leggings and a maroon or brown singlet.

-with AAP