Detective Inspector Chris Ahearn says the woman, 81, was found dead at their home on Thursday afternoon.

The couple's daughter walked into the shocking scene after she dropped into their home because no one there had picked up her phone calls.

Her father was at the home and was taken to hospital, where he's being held under police guard.

"It's very difficult to see people this age, one murdered and (another) facing the courts for such a serious offence," Det Insp Ahearn told reporters on Friday.

"It's a tragic set of circumstances ... with a tragic outcome."

It's uncertain when the woman died, with police suspecting she may have been killed as early at 6pm on Wednesday night.

An axe and a belt found at the home are being examined by detectives.

Officers are reluctant to comment on the severity of the dead woman's injuries.

Det Insp Ahearn said it was appropriate to wait for a post-mortem examination.

"Suffice to say there was some blood at the scene," he said.

The man doesn't have any significant physical injuries, but is undergoing toxicology tests at Gold Coast University Hospital.

Det Insp Ahearn described him as being in "a distressed state" and refusing to answer questions from police.

Detectives haven't established a motive but they're looking into the man's mental health, the woman's medical condition before her death, and whether the man may have been under the influence of a substance.

Police have never dealt with the couple before in relation to any domestic violence matters.

Det Insp Ahearn wouldn't confirm reports the woman had Parkinson's disease or that her partner had dementia.

He also refused to comment on reports the woman may have asked the man to end her life.

"There's various avenues of inquiry being examined to try and determine what was the reason for this lady losing her life," he said.

"We're confident that there is no third party (involved)."

Det Insp Ahearn said the couple's family were co-operating with police, while the daughter who found them was "extremely upset".

He said she was being provided with support, along with police officers and paramedics who first arrived at the home on Thursday.

"It is distressing on our officers who have to respond and the other emergency services, ambulance (workers)," the detective said.

"But you know, we have support mechanisms in place within the Queensland police to support officers in dealing with these issues, that really are quite challenging."

The case was brief mentioned in Southport Magistrates Court on Friday.

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Australian Associated Press