A Brisbane court has heard that sacked LNP media advisor Graeme Hallett threatened to leak information that would “go off like Krakatoa” if he was not given a new job.

Mr Hallett is facing a count of making demands with menaces upon agencies of government, to which he pleaded guilty this week.

The court heard Mr Hallett’s fiery reaction came when he was sacked as media advisor to Bruce Flegg, who was the Queensland Housing Minister at the time in November 2012.

Dr Flegg described the scene in Brisbane's District Court.

“He leapt to his feet and said in a relatively aggressive manner; ‘We'll see about that — I'm going to see the Premier’,” Dr Flegg said.

The court heard that the director of the Queensland government media unit at the time, Lee Anderson, was trying to avoid MR Hallett after he was fired, but bumped into him after a staff member let Mr Hallett into a government executive building.

Mr Anderson said Mr Hallett told him he “wasn't going to take the fall for this”.

“He said Flegg wasn't a fit and proper person to be a minister — hadn't been truthful in terms of his lobbyist register,” Mr Anderson told the court.

“He said that if I didn't find him another job he would make the information public and it would go off like Krakatoa.”

Mr Anderson said he told Mr Hallett to calm down.

“I told him I would let him know if I could redeploy him to another role,” he said.

Mr Anderson agreed under cross-examination that it was possible Mr Hallett was referring to media reactions to finding out he had been fired, but he said this was not his recollection.

Upon hearing quotes from his interview with the director of public prosecutions, Mr Anderson agreed that the Krakatoa comment could have referred to media fallout from Mr Hallett's sacking, not the alleged threat to release information.

The trial continues.