The NSW government will apply to the High Court for special leave to appeal after the Court of Criminal Appeal last week rejected an application by the state’s attorney-general for a man to face a single trial charged with three murders in Bowraville.

Attorney-General Mark Speakman on Thursday said: “I have decided to make an application for special leave to appeal to the High Court.”

“That application will be made in the near future,” he told reporters in Sydney.

“I wouldn’t be making this application unless I believed there were prospects for success.”

A 52-year-old man, who can’t be named for legal reasons, has previously been acquitted at separate trials of murdering two children – Evelyn Greenup, four, and Clinton Speedy-Duroux, 16 – in late 1990 and early 1991.

The NSW government unsuccessfully argued before the appeal court there was fresh and compelling evidence relating to the disappearance of a third child, Colleen Walker, about the same time to justify overturning the acquittals and ordering a retrial.