FIFA said Wednesday it had received no evidence of corruption involving Cameroon as the World Cup took a breather from football ahead of the quarter-finals.
A spokeswoman for the governing body said FIFA had requested all details of communications between Germany's Der Spiegel magazine and notorious Singapore match-fixer Wilson Perumal.
Perumal on Tuesday denied he had predicted the result of Cameroon's 4-0 defeat to Croatia last month, which is now the subject of an investigation by Cameroon's Football Federation.
"We have requested from Der Spiegel all the communications with Perumal and any other material they claim to possess in order to prove the allegations they have made in public," FIFA spokeswoman Delia Fischer told reporters.
"The article has put the integrity of the FIFA World Cup in question which is a serious allegation."
Fischer reiterated that so far none of the 56 matches played at the World Cup had given cause for concern.
"As mentioned on various occasions, FIFA has carefully monitored all 56 games to date and continue to monitor," she said.
"So far we have found no indication of any match manipulation on the betting market in relation to any of the 2014 FIFA World Cup matches."
The Cameroon Football Federation (FECAFOOT) said its ethics committee was looking into Perumal's allegations, reported by Der Spiegel, that he forecast the 4-0 victory by Croatia and that a player would be sent off.
But Perumal issued a strong denial on Tuesday, saying he was "shocked and amazed" at the report of his actions, insisting he had only given an "informal assessment" of the Cameroon-Croatia game with a journalist.
Belgium and Argentina completed the quarter-finalists on Tuesday with victories over the United States and Switzerland to set up a clash in Brasilia on Saturday.
Their qualification leaves the make-up of the quarter-finals evenly balanced with four Latin American sides and four Europeans, giving the 'old continent' a good chance of finally triumphing in a World Cup hosted in the Americas.
The quarter-finals get under way on Friday when France and Germany meet at the Maracana Stadium in Rio de Janeiro before Brazil take on Colombia in Fortaleza.
The Netherlands face minnows Costa Rica on Saturday in the other last eight meeting.
In a sign of the escalating pressure faced by the host nation Brazil, coach Luiz Felipe Scolari called on the team psychologist to give his players an extra session amid concerns his squad is struggling to cope.
Several Brazilian players were reduced to tears during and after the penalty shoot-out win over Chile in the last 16.
Sports psychologist Regina Brandao made an "urgent" and unscheduled visit to Brazil's training camp on Tuesday, ahead of Friday's quarter-final with Colombia, according to a report in the Folha de Sao Paulo newspaper.
Scolari called Brandao on Monday and on Tuesday, she held a meeting with all the players and the technical team, according to Folha. She did not speak individually with players.