Luis Suarez on Friday pleaded his case before the Court of Arbitration for Sport (CAS) to halve his four-month FIFA ban for biting, boosted by a strong show of support from the world players' union.

Barcelona's Uruguayan striker, in a blue checked shirt and jeans, was tight-lipped as he ran the gauntlet of press photographers on his way into the hearing shortly before 10 am local time (0800 GMT).

He emerged almost five hours later, still refusing to comment on the proceedings. He was ferried off in a black van, but not before stopping to sign autographs for some waiting children.

CAS said in a statement that Suarez had given "a statement to the Panel of CAS arbitrators: Mr Bernhard Welten, Switzerland (President), Professor Luigi Fumagalli, Italy, and Dr Marco Balmelli, Switzerland".

Suarez, who has two previous lengthy bans for biting opponents, was banned from all football-related activity for four months after biting Italy defender Giorgio Chiellini on the shoulder during a World Cup group game in the Brazilian city of Natal.

He was also suspended for nine internationals and fined 100,000 Swiss francs (112,000 dollars), FIFA ordering its exemplary punishment because Suarez at first showed no remorse -- he later made a full apology to Chiellini.

He subsequently left Liverpool for Barcelona in a 95-million-euro ($127 million) deal but will currently have to wait until late October before he can play for his new club.

His legal team said on Thursday they were confident of obtaining a reduction of the ban to two months, meaning the former Liverpool striker would be available to play from August 25, and for him to be allowed to train with Barcelona for the duration of his suspension.

CAS said: "At the end of the hearing, the Panel informed the parties that it will issue its decision as soon as possible, probably before the end of next week.

"The full arbitral award, with the grounds, will follow at a later date and be published by the CAS."

Suarez received immediate support from FIFPro, the World Footballers' Association, which called the FIFA sanction "disproportionate".

"That Luis Suarez has been trialed and vilified in public, ever since the incident, is a sanction in itself," FIFPro said in a statement.

"On the other hand, it has been remarkable to see the response from his fellow professionals and the victim himself, Giorgio Chiellini."

FIFPro added: "Many agree the sanctions are excessive. This is an important signal for the CAS panel to consider.

"The sanctions are a disproportionate response to the offence. Especially the four-month ban from all football-related activity, which is unfair for Suarez as it infringes his right to work at club level.

"In the international arena, where the offence was committed, a nine-match ban for Uruguay is also too strong as it effectively equates to a two-year sanction."

FIFPro also stated that "the educative nature of the sanction mentioned by FIFA in the ruling can be much better achieved by making it partially conditional, including the obligation for Luis Suarez to receive treatment".