Six people remain in custody after an investigation by The Sun on Sunday revealed allegations of professional football match fixing.
An undercover investigator from the paper met ex-Portsmouth player Sam Sodje, who allegedly said he could arrange for footballers in the Championship to get themselves a yellow card in return for tens of thousands of pounds.
The 34-year-old also claimed he could rig Premier League games and even said he was preparing to fix matches at next year's World Cup in Brazil, the newspaper reported.
Detectives from the National Crime Agency were still questioning the six men this morning.
Richard Bevan, chief executive of the League Managers' Association, said the organisation had debated match-fixing on previous occasions.
He told The Sun: "What is important is that The FA, Premier League and Football League continue to make sure our game is continuing to move forward.
"Whether it is cricket or football all around the world there are issues in this 24/7 internet and social media world that puts a lot of pressure on.
"There needs to be really strong leadership at the top."
It was also reported that Oldham Athletic player Cristian Montano failed to get a yellow card in return for money in a match against Wolverhampton Wanderers on October 22 and offered to take part in another rigging incident.
Oldham said in a statement: "Oldham Athletic Football Club has been made aware of the incident and allegation surrounding one of its players, Cristian Montano. The club will commence an immediate internal investigation to establish all the relevant facts of the case.
"The club is co-operating with other agencies in this matter and cannot comment on specific facts at this stage. The club will not be issuing any further statements at this time."
An NCA spokeswoman said: "An active NCA investigation is now underway and we are working closely with the Football Association and the Gambling Commission.
"Six people are in custody and are being questioned by NCA officers. We cannot comment further at this stage."
The NCA is already carrying out a separate investigation into an alleged international illegal betting syndicate.
Michael Boateng and Hakeem Adelakun, both 22, were charged last week with conspiracy to defraud contrary to common law.
The pair, who played for Conference South club Whitehawk FC in Brighton, were dismissed by their club and will appear in court on Wednesday.
Two other men, Chann Sankaran, 33, from Hastings, East Sussex, and Krishna Sanjey Ganeshan, 43, from Singapore, were charged last month with plotting to defraud bookmakers and will also appear in court this week.
Speaking about the latest reports, Football League chief executive Shaun Harvey said: "We treat any allegations of criminal activity in our competitions with the utmost seriousness."
The Sun investigation recalls the famous News of the World investigation into cricket match fixing in 2010 which exposed a batting scam involving three Pakistan national cricket team players.