The charges have been adjourned amid legal submissions
Ian Bailey has challenged the statutory right of gardaí to process a drug-driving prosecution against him.
The revelation came as Bantry District Court adjourned four charges against the 62-year-old freelance journalist and law graduate who last year successfully fought extradition to France over the murder of Sophie Toscan du Plantier (39).
Mr Bailey has consistently protested his innocence in relation to the December 23, 1996 killing of the French mother of one at her west Cork holiday home.
The Manchester-born poet was convicted in absentia by a French court of the killing in 2019 but has repeatedly claimed that attempts were made to frame him for the crime.
Mr Bailey described the Paris proceedings as "a farce" and "a show trial".
The French have sought and failed to secure his extradition three times since 2010.
The Bantry District Court adjournment was for legal reasons and the availability of the hearing judge.
Last November, Judge John King heard detailed legal submissions on Mr Bailey's behalf from Emmet Boyle BL, instructed by solicitor Ray Hennessy.
Written legal submissions are now being made on various matters arising.
The counts all arise from an alleged incident on August 25, 2019 near Schull, Co Cork.
Mr Bailey was stopped by gardaí while driving at Skull townsland, outside the west Cork village, and was later taken to Bantry garda station. He was subsequently released without charge.
Mr Bailey later appeared before Bantry District Court on four summonses on the basis of samples taken by gardaí and sent for further analysis.
He faces one summons over allegedly driving while under the influence of cannabis, two summonses over the alleged possession of cannabis and one summons for allegedly allowing his vehicle to be used for the possession of drugs, namely cannabis.
The court was told a small tin of cannabis was allegedly recovered after Mr Bailey had been stopped in his Toyota Verso car by gardaí at a checkpoint. Three rolled-up joints were allegedly later found in his vehicle when it was searched the following day.
Mr Bailey has pleaded not guilty to a total of four charges.
Mr Boyle, on Mr Bailey's behalf, has challenged a number of issues in respect of the matter including how the alleged drugs were found, why the keys of Mr Bailey's car were retained by officers, why the vehicle was moved from the roadside field entrance where it was parked to the garda station, and why it was only searched the following day.
The matter was adjourned for a month.
Mr Bailey has published two successful volumes of poetry and is now the focus of a number of books and two high-profile documentaries.
A television documentary by Academy Award-nominated director Jim Sheridan and investigative journalist Donal MacIntyre is scheduled to get its world premiere in April.