Analysts said revelations about the scale of the scandal could damage Singapore's squeaky-clean image as one of the world's least corrupt nations.
Singapore's role in international match-rigging has long been clear, with Wilson Raj Perumal jailed in Finland in 2011 and another Singaporean, Tan Seet Eng or Dan Tan, wanted in Italy over the "calcioscommesse" scandal.
However, the latest announcement uncovered the huge scale of the activities, and raised potential problems for Singapore's reputation, as well as questions about how authorities are dealing with the match-fixing syndicates.
The Football Association of Singapore (FAS) said it took "a serious view of allegations pertaining to match-fixing and football corruption" and vowed to "spare no effort" to crack down on any such activities.
Zaihan Mohamed Yusof, an investigative reporter with Singapore's New Paper, who is considered a leading authority on match-fixing, admitted he was taken aback by the numbers revealed by Europol.
"This number to me it's huge, 680," he said.
"Whether Singaporeans were involved in the whole 680, I'm not sure but at least there's a figure and you can see the scale there."
And Neil Humphreys, a popular sports columnist and author, asked why "so little is being done to question Singaporean individuals allegedly involved in such a global match-fixing operation".
"More pertinently," he said, "the issue has not received quite the same front-page media attention that it has in other football-popular countries, despite the obvious fact that Singapore is allegedly home to the ringleaders of the world's biggest match-fixing syndicate."
- AAP