Ronnie O'Sullivan has been fined £6,000 by snooker's ruling body for a series of Twitter comments that included his claim that match-fixing could be rife.

The reigning world champion, who landed his fifth Masters title on Sunday night at Alexandra Palace, was charged with breaching the World Professional Billiards and Snooker Association's members rules.

The WPBSA announced that its disciplinary committee assessed the claim - later retracted - from O'Sullivan last September that referred to fixing, a "suggestion he used pills that helped his performance", and a further "offensive" tweet.

In a statement, the WPBSA said O'Sullivan "was fined a total of £6,000 and ordered to pay £1,000 towards the cost of the hearing".

Additionally, the WPBSA said O'Sullivan has been fined £1,000 and warned as to his future behaviour for being "abusive, insulting and disrespectful" to a referee during the German Masters qualifying tournament in Barnsley on December 12.

O'Sullivan made his Twitter remarks about fixing a day after Stephen Lee was found guilty by an independent panel of fixing charges following matches played in 2008 and 2009.

Lee is to appeal against his 12-year ban from the sport and insists he is innocent.

O'Sullivan wrote on September 17: "I've heard there's many more players who throw snooker matches .. I suppose Steve lee was just caught out."

He added that "plenty of people have got loads to hide".

Following an order from World Snooker chairman Barry Hearn to tell all if he knew anything that should be reported, O'Sullivan said in a statement on September 19 that his comments were "out of context in that I was referring back to rumours from many years ago".

It was not enough to spare him punishment, with the ruling body stating on Wednesday: "The WPBSA work hard to maintain what is widely considered to be one of the strongest anti-corruption units of any sport as well as having strong anti-doping policies which involve robust testing schedules.

"The WPBSA disciplinary committee considered that the comments that were made undermined these efforts and were damaging to the image of the sport. Such behaviour will not be tolerated by the WPBSA."

O'Sullivan also wrote on Twitter on September 22 that he was taking "new pills" that meant the "whole world seems to make sense", adding that "u gotta be part of secret society to get em".

The later post, deemed "offensive", was a gratuitous sexual reference that O'Sullivan later deleted.

In Barnsley, he is understood to have taken offence at an instruction by Dutch referee Jan Verhaas to tuck in his shirt before a match. Verhaas was not in charge of O'Sullivan's match but saw him prior to the players entering the arena and told the 38-year-old of the dress code, before being verbally attacked.

The WPBSA announced: "Mr O'Sullivan admitted the allegation and apologised for his behaviour citing conditions at the venue and that he was feeling unwell at the time as the reasons.

"The disciplinary chairman found that he was in breach of the obligations of a player under his players contract with WSL."