A smiling, older woman with long hair sits near a fence on a country property.

Yvonne Whear’s daughter says there is no evidence to suggest her mum left home of her own accord. (Facebook)

Police searching for a missing woman in northern New South Wales say that they cannot rule out foul play as the cause of her disappearance.

Yvonne Whear, 73, was last seen was on the afternoon of February 19, when her car was recorded on CCTV travelling along Queensland Road in the direction of her farm near Murwillumbah in the Northern Rivers.

She was driving her gold-coloured Ford Escape SUV and had previously been seen at the Shell service station on Tweed Valley Way at Murwillumbah at about 3:15pm that day.

Neither Ms Whear nor the vehicle have been since since and her daughter Gillian Hallac says the family is desperate for answers.

“We just want to know where Mum is and what happened to her,” Ms Hallac said.

“If anyone saw anything unusual, no matter how small it may seem, or has any information at all, we urge them to come forward and tell police. Even the smallest detail could make a difference.”

A Ford SUV in a pale metallic colour parked on a country property.

Yvonne Whear’s vehicle was seen on Murwillumbah’s Queensland Road, heading towards the small town of Dungay. (Facebook)

Tweed-Byron Police Detective Inspector Gary Sheehan told reporters that foul play has not been ruled out as the reason for Ms Whear’s disappearance.

“We are looking at all circumstances. In missing persons cases like this, police have to keep an open mind as to what may have occurred, and that’s part of the inquiry that we’re looking at, along with many other inquiries,” he said.

Ms Hallac said the family “strongly believe that someone came to the farm that Thursday afternoon”.

“Mum never liked driving at night and we have no evidence of any reason for her to suddenly leave of her own accord,” she said.

“There were no calls or messages that would explain her leaving. After returning home from her art class at TAFE, she was watching art tutorials, and then after 4:46 pm, everything stopped. She didn’t contact her family again and she did not respond to any messages.”

A missing person sign stuck to a mesh chicken enclosure on a country property.

Yvonne Whear went missing in February. (Supplied)

Police have been searching an area along the Rous River where Ms Whear’s phone was last active and the dive unit is continuing to search the rivers in the area.

“We’ve conducted a number of searches along that area of roadway just in case she’s run off the road, come to some sort of foul play, and we’ve done both sides, so both the north and south along that road, because we simply don’t know,” Inspector Sheehan said.

“We’ve utilised helicopters from both New South Wales and Queensland police forces. We’ve had drones in the air from our rescue squad and we’ve had community organisations like SES doing foot and line searches in the area.”

Anyone with information related to Ms Whear’s whereabouts is asked to contact Crime Stoppers on 1800 333 000 or Murwillumbah Police Station directly.