The 72-year-old rocker believes it is unlikely Waters and Gilmour will agree to a reunion but hopes that the pair, who have only officially reunited once for the 2005 Live 8 charity concerts in 2005, will put their differences aside for another fundraising concert.
The musician tells Classic Rock magazine, "What I think and hope would still be the case is that if there was another Live Aid or a situation where there would be a real purpose in playing again together for something a little more altruistic than making the money, I think the others would step up and do it. And I’d hope that something like that might be possible."
In a recent interview with U.S. comedian Marc Maron, Waters criticised Gilmour and late keyboardist Richard Wright for their actions within the band.
"It was a very toxic environment, when I was around some people – David and Rick mainly – who were always trying to drag me down and trying to knock me off whatever that perch was," he said, adding, "They were very snotty and snipey because they felt very insignificant I think."
Waters is embarking on a solo tour in 2017, while Gilmour recently completed a five night residency at London's Royal Albert Hall.
During his five-night run Gilmour was joined on stage by the actor Benedict Cumberbatch, who sung Waters vocal part from Pink Floyd's 1979 hit Comfortably Numb.