US attorney Michael Garcia also issued a veiled threat to officials such as Franz Beckenbauer who refused to co-operate with the investigation into the bidding for the 2018 and 2022 World Cups that they could face "real penalties".
The Sunday Times has published a number of allegations about payments made to officials, many from Africa, authorised by the now-banned former FIFA member Mohamed Bin Hammam which the newspaper has claimed was to boost support for Qatar's 2022 World Cup bid.
Garcia told the FIFA Congress in Sao Paulo: "Recently there have been assertions about what material I will or will not consider.
"No one should assume what information we have or do not have - we have reviewed the documents and the vast majority has been available to us for some time, well before the recent wave of news report.
"These will continue to be examined and reviewed and we have gone to what appears to be the original source of that data and are confident we will have full access to that before issuing any final report.
"What we cannot and will not do is postpone indefinitely completing our work because someone, somewhere will publish something else.
"It is a process we believe will deliver a report that is comprehensive and fair to all parties."
Beckenbauer stepped down from FIFA's executive committee in 2011 some months after the World Cup vote but still remains on the organisation's football committee.
Garcia said: "The FIFA code of ethics requires all football officials - essentially everyone who has the privilege of working in football - to co-operate with ethics committee investigations and it makes real penalties available against those who fail to fulfil this obligation."
Beckenbauer told German media he did not respond to Garcia's interview request because he did not understand all of the questions sent to him in English.
He said: "Therefore I politely requested a meeting in which we could talk about the matter in German. That was apparently not desired. That aside I wouldn't be able to contribute anything to clear up the matter anyway."
One African official reported by the Sunday Times as having been given money by Bin Hammam insisted that Qatar's bid for the World Cup was never mentioned by the former Asian federation president.
The official, speaking on condition of anonymity, told Press Association Sport: "He said only that he was a friend of African football and wanted to help our federation - the World Cup was never mentioned and of course we did not have a vote for that."
Bin Hammam's patronage is likely to have been targeted at building support for his 2011 challenge for the FIFA presidency, said the official.
Garcia said information had come to him from numerous sources including a whistleblower hotline, the media, football officials and private citizens.
- Sports & Recreation
- Mohamed Bin Hammam
- Michael Garcia
- Franz Beckenbauer