Barbara McCulkin (right) and her daughters Vicky (left) and Leanne (centre) disappeared from their home on January 16, 1974. Contributed

Barbara McCulkin (right) and her daughters Vicky (left) and Leanne (centre) disappeared from their home on January 16, 1974. Contributed

UPDATE: POLICE have charged two men with murder, rape and deprivation of liberty following new information learned in the McCulkin cold case investigation.

Barbara McCulkin and her two daughters Leanne and Vicki, disappeared from their Highgate Hill home in Brisbane on the night of January 16, 1974.

Detective Superintendent Steve Holahan, of the Homicide Group, said the two men had been charged with three counts each of murder and deprivation of liberty, and two counts of rape, and will appear in the Brisbane Magistrate's Court on Monday.

In a press conference from police headquarters in Brisbane this afternoon, Det Supt Holahan said the arrests were made possible after new evidence through new witnesses surfaced.

He said there had been a "significant" amount of new evidence which lead to the arrests.

"Today's arrest is extremely pleasing, but it is only the first step in the prosecution stage, and I'd like to reinforce that," he said.

As the matter is before the courts, Det Supt Holahan said he would not comment on the specifics of the case, except to add the men arrested had been known to police during the 40-year investigation.

He said new motives had been focused on by investigating officers, but would not speculate on the details.

The immediate family of Barbara McCulkin and her daughters had been notified, he said.

"Barbara's immediate family has been contacted and spoken to by investigators and they are being provided all the necessary support by the Homicide Support Group, as needed," he said.

The two men will face a Brisbane Magistrates Court on Monday.

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EARLIER: Forty years after the death of Barbara McCulkin and her two daughters, Leanne and Vicki, police have today arrested a 76-year-old Warwick man and a 67-year-old Torbanlea man.

Barbara and her two daughters Leanne and Vicki disappeared from their Highgate Hill, Brisbane residence on the night of January 16, 1974.

Following an extensive and protracted investigation by members of State Crime Command's Homicide Cold Case Unit and with assistance from the Crime and Corruption Commission (CCC), detectives arrested the men in Brisbane today.

In January this year, a full review of the case was commenced which included speaking with a number of people both in Queensland and interstate and the execution of search warrants on properties in Warwick.

"This has been a full and thorough investigation and review. Many investigators and specialist police over the years have contributed to the evidence in support of these arrests and we are pleased with today's arrest," Detective Superintendent Steve Holahan of the Homicide Group said.

Numerous witnesses believed to have information or evidence relevant to the suspected murder of Barbara, Vicki and Leanne McCulkin have been called to CCC hearings over 31 days since February of 2014. Hearings have been held in Brisbane and in North Queensland.

"The renewed investigation and use of coercive powers has gathered significant evidence without which the arrests would not have been possible," he said.