Queensland Attorney-General Yvette D'Ath said on Tuesday she had asked police to investigate a letter allegedly sent by Senator Culleton to a Cairns magistrate asking for a matter before the court to be adjourned.

On November 15, Senator Culleton wrote to the Cairns Courthouse about a complaint from a person who was facing imprisonment in a Commonwealth matter. The letter foreshadowed a motion in the Senate to recall unnamed judges for "proven misbehaviour".

The letter noted Senator Culleton and others were watching with interest the conduct of all Australian judges after he claimed to have discovered an error relating to the status of the High Court.

"We are watching the with interest the conduct of all judicial officers Australia wide, after discovering the High Court has not been conducting its business in the name of the Queen," the letter reads.

"As a safeguard against a possible injustice, could I respectfully ask that you adjourn the matter until the constitutional position of all courts is clarified."

Ms D'Ath wrote to federal Attorney-General George Brandis after receiving correspondence from Queensland Chief Magistrate Ray Rinaudo, asking for information about what actions the federal government had taken in relation to Senator Culleton's letter.

Ms D'Ath said she was deeply concerned about the matters raised with Judge Rinaudo, which she said could relate to the integrity of the courts and the administration of justice in the state.

It is understood Senator Brandis said any possible offence should be referred to police.

In a statement, Ms D'Ath said she had contacted Queensland Police Commissioner Ian Stewart on Tuesday.

"The Chief Magistrate of Queensland informed me that senator Rodney Culleton, One Nation senator for Western Australia, had written a letter to the Magistrate at Cairns Magistrates Court," she said.

"The Chief Magistrate expressed concern that the contents of the correspondence from Senator Culleton could amount to an attempt to pervert the course of justice, and threatening a judicial officer."

Senator Culleton said he rejected "any suggestion that he threatened any officer of any court or attempted to pervert the course of justice".

He said the letter had been written "in good faith and in the interest of justice".

Senator Culleton is facing expulsion from the Senate after the government challenged his eligibility in the High Court because of a previous conviction for larceny, later annulled.

The case will be heard in December after a directions hearing in Canberra on Monday.

One Nation leader Pauline Hanson said the letter had been sent without her knowledge, or that of the party's other senators.

"I have called for an urgent meeting [on Tuesday evening] with Senator Culleton to explain his position," she said.