"The authorities in Singapore are assisting the European authorities in their investigations into an international match-fixing syndicate that purportedly involves Singaporeans," the Southeast Asian city-state's police said in a statement.
"Singapore takes a strong stance against match-fixing and is committed to working with international enforcement agencies to bring down transnational criminal syndicates, including those that involve the acts of Singaporeans overseas, and protect the integrity of the sport."
In a scandal that has tarnished the world's most popular sport but which some pundits have said is old news, about 680 suspicious matches have been identified in an inquiry by European police forces, the European anti-crime agency Europol and national prosecutors.
A German investigator described a network of couriers taking bribes around the world to pay off players and referees.
"We have evidence for 150 of these cases, and the operations were run out of Singapore with bribes of up to 100,000 euros ($135,600) paid per match," said Friedhelm Althans, chief investigator for police in the German city of Bochum.
Singapore allows suspects to be sent only to countries with which it has an extradition treaty. Germany has such a treaty with the regulated, wealthy Asian city-state but Italy, which made the original complaint about match-fixers, does not.
Extradition also requires "common criminality" - a suspect must have allegedly done something illegal in Singapore that gives its police the grounds to detain him. ($1 = 0.7376 euros)