Three Lebanese football referees pleaded guilty Monday to accepting free sex from a gambling-linked global syndicate in return for agreeing to rig a match, with a Singapore judge jailing two and deferring sentencing for the third.

A district court judge jailed assistant referees Ali Eid, 33, and Abdallah Taleb, 37, for three months. He deferred sentencing till Tuesday for referee Ali Sabbagh, whom state prosecutors said was the most culpable.

The assistant referees broke down into sobs and repeatedly looked up as if to thank God when Judge Low Wee Ping said they could be freed by later Monday or Tuesday, after remission for good behaviour and due to time already served awaiting sentence.

Turning to Ali Sabbagh, 34, the judge said: "I need time to consider your sentence. I don't, for the moment, accept that you should be sentenced to six months."

Deputy public prosecutor Asoka Markandu described Ali Sabbagh as "the most culpable" among the three as he was the one approached by the syndicate and the one who persuaded the two linesmen to accept the sexual bribe.

The three men were arrested and charged on April 4 with corruption for accepting sexual favours in exchange for agreeing to fix an unspecified football match.

They had been abruptly pulled out of an Asian Football Confederation Cup match they were scheduled to officiate in Singapore on April 3 between Singapore-based club Tampines Rovers and India's East Bengal.

The three were denied bail and have been detained at Singapore's Changi prison since April 4.

Eric Ding Si Yang, 31, a Singaporean businessman who allegedly supplied the prostitutes, has also been charged with corruption and granted bail.

The judge lashed out at the FIFA-accredited referees for bringing disrepute to the sport, saying they were probably the first international football match officials to be charged with corruption in Singapore.

"That alone, the fact that you are international officials, in my view, is already an aggravating factor," he said.

"The Singapore public has an interest in preserving football as a professional sport in Singapore. This is because it has social, recreational and economic value," he added.

Defence lawyer Gary Low cited his clients' previously unblemished records, their guilty plea and the fact that their acceptance of the sexual bribe did not result in any football match being rigged.

"The gratification was arranged by Mr Ding Si Yang with a view to fixing a football match in the future. Our clients did not reach an agreement with Ding to fix a particular football match," Low said.

"In these circumstances, our clients' conduct did not in any way affect or influence the outcome of any football match."

State prosecutors have said Ali Sabbagh, a sports teacher with Lebanon's education ministry earning $850 a month, was approached by Ding in "mid-2012" in Beirut, indicating a "clear international dimension" to the offences.

Ding, described in Singaporean media as a nightclub owner who drives an Aston Martin sports car, is facing three counts of corruption charges but was freed after posting bail of Sg$150,000 ($121,000).

Singapore has a long history of match-fixing, and syndicates from the wealthy Southeast Asian island have been blamed by European police for orchestrating a network responsible for rigging hundreds of games worldwide.