Samantha Murphy's father is breaking his silence about his frustration over one factor in the police investigation

The heartbroken father of missing mother-of-three Samantha Murphy has expressed his frustration at not being able to talk openly about his beloved daughter's disappearance.

While the search for Ms Murphy is being reduced to the efforts of a team of local sleuths, John 'Pud' Robson told Daily Mail Australia that police have told him to keep his mouth firmly shut.

'Forget it mate. I'm not allowed to say 'boo,'” Robson said Tuesday afternoon.

“The police asked us not to all say 'thunder'.”

When asked why he could not talk about his daughter, Mr Robson said the police had told him all the information about her and that the investigation would come from them.

“Anything that is released, they will release,” he said. “We're not talking about size. Thank you very much.'

Mr Robson said he hoped news would come 'soon'.

'But don't worry about that. There's not much anyone can do until something comes up. Thank you for your efforts,” he said.

When asked how he and his family were doing, he replied, “How do you expect us to be doing?”

Last week, Mr Robson's sister-in-law Janice Robson told Daily Mail Australia that Mr Robson had been keeping himself busy by returning to work driving trucks on the highway.

Jan went back to work. He said: “There's nothing I can do,” Ms Robson said.

“And I think if we were put in that position, we would be like that ourselves.”

Samantha Murphy's husband Mick Murphy appeared shocked after speaking to police in the early stages of the search on February 7

Kind-hearted locals have continued the search for Ms Murphy in rugged terrain

Mrs Murphy's father had called his brother Allan and Janice just as they were about to have dinner the night she went missing.

“He said, 'Oh Janice, Sam's gone. Samantha's missing,'” Janice said.

“I said, 'What do you mean missing?' He said, “She's missing. She went outside.” He didn't say she had gone jogging, but that she was missing. 'She didn't show up. She never came back.”

Allan said he asked his brother if he knew of a reason why his daughter might have disappeared, but he had no answers.

It is understood that both Allan and Janice Robson have since been told not to speak to media representatives for fear of 'spoiling the police investigation'.

Police and emergency services virtually abandoned the search for Ms Murphy within a week of her being reported missing.

Police on horseback walk past Murphy's home in the days after Samantha Murphy disappeared

State emergency services crews called off the search within a week after Ms. Murphy went missing

By then, Victoria Police's Missing Persons Unit had taken over the investigation and immediately focused its efforts on friends and family of the missing 51-year-old.

On Tuesday, a group of volunteers, organized through social media, were the only bodies on the scene as they continued to search the dense bush where Ms Murphy was last seen.

Mrs. Murphy's husband Mick Murphy told it Herald Sun public support has been strong and the search efforts have been extraordinary so far.

'We [would] I would like to thank everyone who spent time looking for Sam,” Mr Murphy said.

“I hope we can find something soon.”

The group, known online as the “Ground Crew,” organized a local search Saturday morning from Eureka Stockade Memorial Park, just off Eureka Street.

Ms Murphy left her home on Eureka Street in East Ballarat, northwest of Melbourn to go running in the Woowookarung Regional Park jon February 4 after 7 a.m. and has not been seen since.

State emergency services volunteers and police initially searched the bush in an area between the Canadian Plantation and Yankee Flat Road – about 15km from Ms Murphy's home – where they believe her phone was switched off.

Anyone with information about Samantha Murphy's disappearance can contact Crime Stoppers on 1800 333 000.