The Union of Fans said many of the Ibrox faithful would turn their backs on Rangers if Mr Green was to return, and blamed him for the club's parlous financial state.
Mr Green last night claimed he was close to a deal that would raise £10 million with Soros Fund Management - a company run by one of the world's richest men - said to be involved and to have already contacted Rangers.
He told the BBC: "What I'm saying is: if someone else can raise the money then great. If not, I'll do it.
"I've made loads of mistakes. I'm not saying I'm a good guy but I'm certainly not the worst guy.
"I wouldn't be involved at executive level or operationally, but if I bring investors in, they'll want some kind of representation on the board. That could be me or someone else."
Mr Green left the Ibrox club last year following allegations about business dealings with former owner Craig Whyte. The Union of Fans, a leading supporters group, said: "Simply put, Charles Green is not welcome at Rangers and we believe any attempt by him to return would see a huge number of Rangers fans seriously consider a full boycott of the club.
"It appears that Mr Green is struggling to maintain his grasp on reality if he thinks Rangers fans will accept a further pillaging of the club by his clients.
"The £10m, even if it exists, is a sticking plaster on a gaping wound and made all the worse by Green's record of siphoning any money invested in the club straight back out."
The current board also ruled out working with Mr Green again, with chairman Sandy Easdale saying: "I am delighted that anyone would invest in Rangers - Dave King, George Soros, Charles Green or Uncle Tom Cobley - but I am not part of any concert party with Charles Green."