An arrest warrant has been issued for US cyclist Floyd Landis, who is accused of hacking into a French drug-testing laboratory, France's anti-doping authority (AFLD) said.

Pierre Bordry, head of the AFLD, said Landis used documents "illegally hacked from the authority's laboratory computer system" in his defence after he was stripped of his 2006 Tour de France win following a positive drugs test.

The warrant was issued by a French judge on January 28 in response to the failure by 34-year-old Landis to answer a summons issued in October, Mr Bordry said.

The judge intends to ask Pennsylvania-born Landis "to explain how he came to obtain certain information that was used in his defence," added Mr Bordry.

Arnie Baker, a former American rider and cycling coach, for whom an arrest warrant was issued in November, is also being sought by the French authorities in connection with the affair.

Landis tested positive for testosterone during the 17th stage of the 2006 edition of the world's most famous cycling race.

He had won that stage in spectacular fashion with a solo attack which virtually secured him the yellow jersey only 24 hours after a dramatic collapse on stage 16.

He was stripped of his Tour de France win in September 2007, more than a year after he crossed the finishing line on the Champs Elysee in Paris.

He was banned from racing for two years, making his return in January 2009.

During that time he carried on the legal fight to the Court of Arbitration for Sport (CAS), sports highest appeal authority, who threw out his case in June 2008.

As well as rejecting his appeal CAS ordered him to pay $US100,000 in judicial costs to the American anti-doping agency (USADA).

Landis' attempts to clear his name have cost the rider an estimated $US2 million.

CAS itself has spent almost the entire $US1.8 million budget set aside to ensure Landis' attempt to appeal his ban failed.

The accusation of hacking first arose when the Paris suburbs-based AFLD lodged legal proceedings on November 7, 2006 after becoming aware that documents belonging to them had been used in Landis' defence.

According to sources close to the inquiry, the electronic paper trail led them to Baker's computer address.

During his ban, Landis had hip surgery and worked as an adviser to American cycling outfit Rock Racing.

On his return to competition he joined the OUCH Pro Cycling Team. His first race back from suspension was in the 2009 Tour of California.

Landis, who became a professional mountain biker aged 20 and who had a spell riding for the US Postal team alongside seven-time Tour champion Lance Armstrong, has since competed in the Tour of Southland in New Zealand.

- AFP