Swiss prosecutors are looking into 53 possible cases of money laundering as part of their investigation into Fifa's awarding of hosting privileges of the 2018 and 2022 World Cups.
Switzerland's attorney general, Michael Lauber, said his office (OAG) has seized "nine terabytes" of data as part of the corruption inquiry which has so far brought evidence concerning 104 "banking relations".
Domenico Scala, head of Fifa's audit and compliance committee, has previously said there could be a re-vote if allegations of bribery involving the two countries are proven to be true.
The Swiss investigation is running alongside an FBI inquiry which resulted in seven Fifa executives being arrested at a hotel in Zurich over corruption allegations.
Giving an update on the investigation, Lauber said: "Our investigation is of great complexity and quite substantial. To give you an example: The OAG has seized around nine terabytes of Data.
"So far, our investigative team obtained evidence concerning 104 banking relations; be aware that every banking relation represents several bank accounts. This implies that the OAG has to process huge amounts of data.
"We note positively that banks in Switzerland did fulfil their duties to file suspicious activity reports. Partly in addition to the 104 banking relations already known to the authorities, banks announced 53 suspicious banking relations via the Anti-Money-Laundering-Framework of Switzerland."
Lauber added the scale of the "huge and complex" investigation means the inquiry and any prosecutions will take some time.
He added: "The world of Football needs to be patient. By its nature, this investigation will take more than the legendary 90 minutes.
"Be assured: The OAG will give priority to this case and will act according to the principles of the rule of law. There will be formal interviews of all relevant people. By definition, this does not exclude interviewing the president of Fifa or its secretary general."
Blatter is not currently involved in either of the corruption and bribery scandals surrounding Fifa. He announced his decision to stand down as the head of the football's world's governing body just four days after he was re-elected.