European police warned Monday that the integrity of football was at stake, as they revealed they had smashed a criminal network fixing hundreds of matches, including in the Champions League and World Cup qualifiers.

Europol said a five-country probe had identified 380 suspicious matches targeted by a Singapore-based betting cartel, whose illegal activities stretched to players, referees and officials across the world at all levels of the game.

"It is clear to us that this is the biggest investigation ever into suspected match fixing," Europol chief Rob Wainwright told a news conference in The Hague, adding that the fall-out hit at the heart of the world game's reputation.

"It is the work of a sophisticated organised crime syndicate based in Asia and working with criminal facilitators around Europe."

Wainwright said he would be writing to the head of European football's governing body UEFA, Michel Platini, but said all of football needed to "heed the warning" and be on their guard.

The revelations come after Interpol last month warned that global football corruption was helping to fuel the criminal underworld's domination of prostitution, drug-trafficking and gun-running and in the wake of several high-profile scandals.

They include the so-called "calcioscommesse" or illegal football betting affair in Italy, which overshadowed the country's preparations for last year's European championships and saw several top footballer's arrested.

In the latest claims, Europol said that at least 425 referees, players and other officials were suspected of involvement, with matches rigged so that major sums of money could be won through betting.

Most of the allegedly fixed matches were played in the Turkish, German and Swiss championships, but other matches around the world are also concerned.

Two of Europe's Champions League matches and some World Cup qualifiers are also suspected, Europol said.

No details were given about which top-flight matches were involved because some investigations were still on-going, although it was revealed that one of the Champions League matches had been played in England.

Criminals made over eight million euros ($11 million)in profits from betting on fixed matches.

Europol showed television coverage of a suspect match, an international between Argentina and Bolivia, during which a Hungarian referee awards a highly dubious penalty.

The probe was carried out by Europol and five European countries: Germany, Hungary, Slovenia, Finland, Austria.

A further 300 suspicious matches have been identified outside Europe in Africa, Asia, and South and Central America, Europol said.

German chief investigator Friedhelm Althans said that showed "the true horrifying nature of the problem" and the implications were stark, including financial losses for legal betting firms, clubs, players and the trust of the supporting public.

"Operating from Singapore by heads of this organisation, bribes of up to 100,000 euros per match were paid in cash, which was taken all over the world by money couriers," he added.

FIFA's own "corruption-buster", former Interpol executive Ralph Mutschke, also said last month that no league in the world was safe from corruption, amid calls for common legislation to tackle the scourge of bribery in sport.

The international nature of match-fixing was highlighted by the case involving Singapore businessman Wilson Raj Perumal, who was suspected of rigging games in several countries and was jailed in Finland in 2011.

His name was also cited in cases in South Africa and Zimbabwe.