NewFIFANow founder Jaimie Fuller said Sepp Blatter's announcement of his resignation will not single-handedly clean FIFA of corruption.
Fuller, chairman of sportswear company Skins, said the fact 133 federations voted in favour of the 79-year-old Swiss at Friday's presidential election in Zurich was proof more needed to be done to weed out the lack of transparency in world football's governing body.
"We've been pushing for the implementation of an independent reform commission to completely review; their statutes, their constitution, their committees, their structure... What we cannot do now is leave the future of FIFA in the hands of Mr Blatter's cronies," Fuller said.
"This must not be allowed to happen and we have to be careful that we're not lulled into a false sense of security now that Mr Blatter has gone.
"Otherwise it will be just like arranging deck chairs on the Titanic."
Fuller said supporters of Blatter should be closely monitored as the organisation looks towards a new era.
"No doubt there will be a power struggle," the Australian, who is based in Switzerland, said.
"Already we've seen Domenico Scala step into a bit of a void, a vacuum. I'm personally not encouraged by his taking that role.
"He was one of Blatter's cronies and I look to him as being part of the problem.
"Therefore, that's why we believe the sponsors really need to stress the need for some form of independent review, to make sure that we don't end up where we are today."
Fuller said Blatter resigned as "the FBI are closing in on him", and he would have wanted to avoid being in the role if he was being personally investigated.
"I don't believe Mr Blatter can avoid prosecution, I don't believe Mr Blatter can avoid an investigation," he added.
"I think Mr Blatter is probably decided that he would rather this happened with him not being in the spotlight and him not being in the president's chair.
"And I think that is probably one of the reasons, if not the reason, why Mr Blatter has chosen to resign yesterday."
