Park scoured for remains in Qld cold case

Police are combing national parkland for the bodies of two men believed murdered 25 years ago in central Queensland.

A search zone established within the Kroombit Tops National Park was on Friday scoured by 60 SES volunteers, 10 police officers and a cadaver dog for the bodies of Robert Grayson and Derek Van Der Poel.

Mr Grayson, then 26, and Mr Van Der Poel, 23, were last seen alive in Gladstone in May 1993.

The pair had been minding substantial marijuana crops for Russell James Williams, 51, who was charged on Monday over the murders.

Detective Inspector Darrin Shadlow admitted there had been several searches in the national park before new information had come to light since Williams was detained.

"Since the arrest of Mr Williams we have received some information from members of the public," Det Insp Shadlow said.

"Some people have stated they have come forward since the arrest, they do feel more comfortable.

"We just ask that people look inside themselves and look at their conscience."

The area carefully examined by authorities on Friday included where the crops were grown as well as adjoining land, with the search expected to continue on Saturday.

Det Insp Shadlow said investigators had identified multiple persons of interest but he refused to elaborate on what roles they were suspected of playing in the men's disappearance.

Williams faced Gladstone Magistrates Court briefly on Tuesday charged with two counts of murder and drug production, with the matter adjourned to April 10.

More than 100 people have been questioned by detectives and a $250,000 reward remains in place for information.