(CNN) -- FIFA was under growing pressure Sunday after one of its key sponsors demanded an investigation into corruption allegations published in a British newspaper over the controversial award of the 2022 World Cup to Qatar.
In its second batch of reports, Britain's Sunday Times made a series of new revelations, centered on the role of Qatar's former top football official Mohammed bin Hammam, in the nation's bid to stage the global showpiece.
Electronics giant Sony, listed as one of FIFA's six key partners, wants the world governing body to act promptly.
"We expect these allegations to be investigated appropriately, and continue to expect FIFA to adhere to its principles of integrity, ethics and fair play across all aspects of its operations," Sony said in a statement to CNN.
The reports come the day before FIFA officially concludes its own probe into the 2018 and 2022 bids, won by Russia and Qatar.
It is being led by its chief investigator Michael Garcia, the former U.S. attorney who is to make his findings public in mid-July through FIFA's new adjudicatory chamber.
Sportswear company Adidas, one of the other five partners, also voiced its concern Sunday over the issue.
"A report is due to be submitted to the adjudicatory chamber of the FIFA Ethics Committee, with findings then released publicly in due course. We are confident that the matter is being dealt with as a priority," Adidas said in a statement released to CNN.
"Adidas enjoys a long-term and successful partnership with FIFA that we are looking forward to continue. Having said that, the negative tenor of the public debate around FIFA at the moment is neither good for football nor for FIFA and its partners."
Another main sponsor, Visa, said it's taking a wait-and-see approach.
"We understand FIFA is taking this matter seriously and we will continue to monitor its internal investigation," it said. "We expect FIFA will take the appropriate actions to respond to the report and its recommendations."
The six main FIFA sponsors are believed to have collectively paid around $180 million as part of their sponsorship agreements.
Sony's deal is due to expire this year having been in place for the 2010 and 2014 World Cups.
Among the latest Sunday Times allegations were claims that bin Hammam had acted as a broker between Qatari officials and governments to set up lucrative bilateral trade deals as an incentive to gather support for their bid.
The newspaper insists it has had access to millions of emails, documents and bank records to show bin Hamman used a $5 million slush fund to influence the bidding process, but CNN has not had access to this material to verify its accuracy.
Bin Hammam refused to directly respond to the Sunday Times allegations, but told the newspaper he believed "that the truth will find its way to (the) public one way or another."
The 63-year-old first came to prominence when he challenged Sepp Blatter for the FIFA presidency in 2011 but was forced to withdraw to fight bribery allegations.
He was later cleared of the allegations, but in 2012 he was banned for life by FIFA's ethics committee for "conflicts of interest" while president of the Asian Football Confederation.
Qatar World Cup organizers have continually denied that bin Hammam had any official or unofficial role in the bidding process and remain confident that they will not lose the rights to stage the competition.
In response to the latest reports, the Qatar 2022 Supreme Committee for Delivery and Legacy released a new statement to CNN.
"In regards to the most recent allegations by The Sunday Times, the Supreme Committee stands by its previous statement," it said.
"There is an ongoing investigation into the 2018 and 2022 World Cup bid process with which we have fully cooperated," it said.
"Qatar has won the bid on its merits and we are confident at the end of the appropriate process, the award of the 2022 World Cup to Qatar will stand."
From the moment the decision was made in late 2010 for Qatar to become the first Arab state to host a World Cup finals, there has been a series of controversies.
The extreme summer heat, with temperatures as high as 50 degrees C, has led to calls for the tournament to be switched to a date during the European winter -- coming into conflict with the major football leagues such as the EPL and La Liga
FIFA has also called for improvements in conditions for migrant workers amid damning reports from international labor organizations and Amnesty International.
With the 2014 World Cup in Brazil due to start Thursday, FIFA officials have been gathering in the South American country for their annual Congress in Sao Paulo between June 9 and 12.
FIFA president Sepp Blatter is expected to announce his candidacy for a fifth four-year term as head of the organization.
FIFA has made no official comment on the latest allegations but Blatter took to social media to defend FIFA's handling of the affair.
"Never ignoring media reports on ethics allegations in football. But let the Ethics Committee work!" he tweeted.
CNN's Khushbu Shah contributed to this report.