Missing Kiwi Linda Frances Sidon - police search for traces of blood

Linda Sidon, who had been living in the Gold Coast at the time of her disappearance, was last seen in June 2009. Photo / Supplied

Australian police are searching for traces of blood at the former Gold Coast home of New Zealand woman Linda Sidon.

In August, Queensland police announced that Ms Sidon's 2009 disappearance - initially a suspected suicide - was now the subject of a murder investigation.

The part-time cleaner, who was also known as Linda Jackson, was reported missing nearly 18 months after she was last seen alive on June 21, 2009.

Her son, now aged in his late 20s, was announced as a person of interest by police as they began searching bushland in the Numinbah Valley for her body in August.

Queensland Police told reporters today they were searching the woman's former Ashmore home for traces of blood.

Ms Sidon was a single mother who reportedly lived a lonely life with her son in a housing commission unit.

When she went missing, it was more than a year until her elderly father in New Zealand contacted his local police, concerned that he had not heard from her. They then passed the information on to Gold Coast detectives.

At the time Ms Sidon's history of anorexia, anxiety and depression led police to believe she had committed suicide. But new information led to her disappearance being treated as suspicious.

Southeast police regional crime co-ordinator Detective Superintendent Dave Hutchinson said there had been no proof of life since June 21, 2009.

He said there was new technology that would allow police to search for traces of blood even under paint.

It has been six years since Ms Sidon last lived in the Gold Coast home - and the housing commission property now had a new occupant, who has agreed to move out while the search is undertaken.

"Obviously we would be looking for signs of blood. Although six years has passed that's still a reasonable possibility ... we also have laser technology these days which will allow us to identify blood under paint, that sort of stuff.

"We'll have to wait until we get there, let the scientific officers and our forensic police have a look at the scene and see which way they think it's best to go."

Ms Sidon's son was still a person of interest and had been spoken to by police a number of times, Mr Hutchison said.

He said a "major" search of bushland in the Numinbah Valley will also be conducted by police within the next two to three weeks, including excavation and possibly damming the creek to stop the water. It was expected to take some time.

Mr Hutchison said past information from the public did not lead police to the recent searches.

"That's just the way things evolve. The investigation started ... and we just follow the evidence. The evidence has led us to this at this point."

Ms Sidon was a "fairly socially isolated" person but police would still like to hear from anyone who had contact with her around June 2009.