There have been major developments in a cold case murder in Canberra 15 years ago, ACT police say.

On Saturday November 6, 1999, two men forced their way into the McKellar home of elderly couple Gregor and Irma Palasics.

The intruders bound, gagged and viciously bashed the couple and ransacked the home, stealing money and jewellery.

After the offenders left, Mr Palasics was able to free himself and phone police but Mrs Palasics, 72, died from her injuries.

Mr and Mrs Palasics were robbed in 1997 and 1998, and police suspect all three robberies are linked.

Police are renewing their call for public information about the murder, saying there have been major developments in the investigation.

But they are yet to publicly detail what new information has come to light to help their investigation.

In 2012 the couple's daughter Liz Mikita told the ABC two people died that night.

Her father, severely injured, traumatised and grief stricken, died within the year.

"They were virtually tortured that night," she said.

"They were viciously attacked and unfortunately mum didn't survive the attack.

"Dad didn't want to but he had to live it seems for some reason, I don't know what."

In 2012 ACT Policing announced they were seeking four teenagers who broke into the Woden Pitch and Putt in 2010.

Officers said there could be a forensic link between the aggravated burglary at the Pitch and Putt and the murder of Mrs Palasics.

Police continue to offer a $500,000 reward for information that leads to the resolution of the case.