They also voice backing for the move by Jim McColl's group to oust chief executive Craig Mather, finance director Brian Stockbridge, and fellow director Bryan Smart.
The statement, issued by the Rangers Supporters Assembly, the Rangers Supporters Association, and the Rangers Supporters Association, reads: "There are significant concerns among our worldwide fan base over the conduct of former CEO, Charles Green.
"Mr Green has been very outspoken in the media, and has clearly undermined the manager and the team. He is also purported to be giving support to a financial claim to be made against the club which we feel represents a conflict of interest for him and the club.
"We strongly urge the board to terminate Mr Green's consultancy role and make a clear decision to either accept the requisition to make changes to the board, or confirm the date of the EGM.
"In the event that an EGM is necessary, we will canvass supporters' opinion on the matter, and the trust will use its vote in accordance with the instructions of the members.
"At this stage, however, we believe it in order to recommend that all fans who are shareholders to vote, or proxy their votes to support the proposed motion to replace three current board members. We will provide further guidance on how this can be done if and when the EGM is confirmed
"We were greatly concerned at the fans' meeting on August 8th to learn that there is only £10m in the club's account. This is especially worrying considering the club has benefited from two seasons worth of season ticket sales (over 70,000) as well as the £22m raised in last year's IPO.
"From the wording of the EGM requisition, and the media comments of Jim McColl, we understand the requisition does not mean a potential takeover of the club but is an attempt by a large group of shareholders to have their views represented on the Board and to bring much-needed stability to the club.
"We are confident that fans will support Mr McColl and his colleagues and we can also work with them towards a fan ownership/representation model. Mr McColl has confirmed to us that he remains supportive of fan ownership/representation and will look to explore this further when the club has been stabilised.
"All Rangers fans expect the Board to act decisively when they meet on Tuesday."