Updated

Singapore confirmed Wednesday it was holding four alleged members of a global football match-fixing syndicate under a law allowing indefinite detention, while it builds a case against them.

The announcement comes a fortnight after Singaporean authorities rounded up 14 people in their biggest crackdown yet on international match-fixing.

Nine of them have been released on bail.

A government statement said four others are being held under the Criminal Law (Temporary Provisions) Act (CLTPA), which is typically used against gangsters.

Their names were not disclosed but a source told AFP that Singaporean businessman Dan Tan, the suspected syndicate leader, is one of them.

The statement said a fifth person has been issued with a police supervision order under the law, curtailing the suspect's movements.

A special committeee will be convened within the next 28 days to assess the merits of the detention orders, and the four will be allowed to make legal representations. The fifth suspect will also appear before it.

The committee will then submit a report to President Tony Tan, who will give the final assent to the detention and police supervision orders.

The CLTPA allows authorities to hold suspects indefinitely, with yearly reviews.

An average of 37 detention orders and eight supervision orders were issued each year from 2009 to 2012, according to the Ministry of Home Affairs.

Experts say gangs in Singapore have cultivated links with foreign criminals to fix games in different countries, for the purpose of illegal gambling.

Interpol chief Ronald Noble has said the industry has revenues of billions of dollars a year.

After the arrests in Singapore, Noble said the gang was the world's "largest and most aggressive match-fixing syndicate, with tentacles reaching every continent".

Noble, who had previously called for the arrest of Dan Tan, whose full name is Tan Seet Eng, added that "the mastermind was someone many believed was untouchable".

Singapore's links with match-fixing have been in the spotlight since the arrest and jailing of Singapore's Wilson Raj Perumal for match-fixing in Finland.

Perumal, who claims to be a former associate of Tan's, is now reportedly under police protection in Hungary.

However, reports have named him as a suspect in a multi-million-dollar fixing ring revealed this month in Australia's state league.