Officers combed Neils Reserve for the remains of Ruth Ridley on Wednesday, including a site where one of her sons has carved the word "mum" with a cross into a tree.

The Port Macquarie grandmother stayed at the site with her estranged husband Gary, with her last sighting overnight on October 26 and 27.

Mr Ridley is thought to have killed the 58-year-old before taking his own life in her car.

A NSW Police cadaver dog searched the area with uniform police and Wodonga family violence investigators in the hope of making a discovery which could bring answers to her two sons, Steven and Nathan.

Detective Leading Senior Constable Andrew Leonard said he was confident if her remains were at the camping area, they would be found, but said other sites had also been identified.

"We're looking for potentially a body here today," he said at the scene.

"The dog is trained for this purpose and it's a resource we've been able to utilise and we're hopeful of actually having a successful find.

"It's been a major impact on the family as you can expect.

"We will be suggesting to the coroner it's a murder-suicide case. The family have been quite impacted in relation to that.

"We've been able to provide a certain amount of support as all police do, however for now it's hoped to at least provide the family closure and provide further answers for the coroner."

Police scoured the area in November last year.

Bushfires prevented further searches, and a search planned in March which was hampered by COVID-19.

Further complicating a possible burial site is that Mr Ridley drove 50-plus kilometres to Tumbarumba after the suspected killing, leaving a huge potential search area.

But information and investigations suggested the campsite could hold her remains.

"There's been a lot of information, a lot of history gathering and also a lot of assessment," Detective Leading Senior Constable Leonard said.

'So there's information suggesting to me that it's here, and it certainly warrants us having a look."

The search was planned to run two days.

"I just can't imagine what it's like not having any answers to what's actually happened to your family," Detective Leading Senior Constable Leonard said.

"The opportunity for us to attempt to provide closure to the family is significant.

"It means a lot to us but it also would matter to the family."

Groups of campers who stayed near the couple remain elusive.

Police believe four other campsites were being used at Neils Reserve while the Ridleys stayed there on the last weekend of October last year.

A Wodonga man has spoken to police, notifying them that the other groups had been there at the time, but the campers haven't come forward.

"A lot of the purpose of today is also to request further help from the public," Detective Leading Senior Constable Andrew Leonard said.

"We're hoping the remaining groups can come forward, particularly given it's a week past that 12-month anniversary.

"It might just make people remember they were camping there at the time"

It's unclear if the other campsites had just one or multiple occupants.

The detective estimated police had spent more than 1000 man hours on the case, which will be presented to the coroner.

If this week's search doesn't find Mrs Ridley's remains, police will go back to the drawing board to figure out where else to search.

Police planned to use the cadaver dog closer to Wodonga if nothing is found at Neils Reserve.

"We have had relatively constant contact with the family," Detective Leading Senior Constable Leonard said.

"They are supportive of the police action. They're keen themselves to get closure. I totally understand that and that's what we're looking for."