Cardiff City fans have organised an "emergency meeting" to discuss how they will respond to controversial plans to change the club's colours and badge.
City's Malaysian owners want to change the home kit from blue to red, with a dragon instead of a bluebird crest, and ditch the nickname of the Bluebirds.
But they also propose investing £100m, with an expanded stadium, new players and a new training ground.
Supporters are meeting at the Municipal Club in City Road on Saturday.
Cardiff City Supporters' Trust has written to MPs and AMs to invite them to the meeting - jointly organised with Cardiff City Supporters' Club.
The letter raises concerns about the plans which the trust says would "end a century of tradition by replacing the famous blue shirt of our city's football club".
"Their intention for Cardiff City to play in red and to change the club's badge from the bluebird to a red dragon has been announced without prior consultation with the club's supporters, supporters' representatives or the local community," said the letter.
"The Cardiff City Supporters' Trust Board believe that any move to change our club's identity represents a diminution of the identity of the club, its supporters and football in south Wales.
"As a result we are calling on the support of community leaders and representatives across south Wales in demanding that the football club holds a full and thorough consultation with its supporters and supporter representatives to decide what is the colour that best represents Cardiff City."
The trust has said it wants to canvass supporter opinion which is why Saturday afternoon's meeting has been organised.
The proposals for the Championship club include increasing the capacity of the Cardiff City Stadium to 35,000 by 2014, as well as new training facilities and money to buy players.
But there has been a mixed reaction to the rebranding from supporters so far.
Fans' views on unofficial City message boards appear mostly hostile to the changes, but there are supporters backing the plans.
It is proposed Cardiff will play in red shirts, black shorts and red socks with a blue away kit, while the club's badge would have a dragon on it instead of a bluebird.
The club's Malaysian investors believe red is a more dynamic colour for marketing in Asia, as well as of more national significance in Wales.
While the shirts and club badge could change colour, Cardiff City sources categorically deny that the club - nicknamed "the Bluebirds" - will become known as "the Red Dragons''.
Sports and heritage minister Huw Lewis AM said: "It is not for government to tell football clubs what to do in terms of branding - and potential investment in any of our elite sports clubs is of course welcome.
"However, supporters are the life blood of club football and their views should be of paramount importance when it comes to any fundamental changes."
Former Cardiff City captain Jason Perry believes Cardiff's home shirt should remain blue.
"The Malaysians are very successful business people in terms of raising money and in turn you can invest more into the football club in terms of facilities and players," he said.
"But it's not for me. I think football is about identity. I wouldn't want to see the soul of the club sold for millions to be invested in.
"Cardiff City is blue and should always be blue."
Former City player Joe Ledley, who now plays for Celtic, Tweeted: "I can't believe what I'm hearing, CCFC wanting to replace the Bluebird. The Bluebird is a legacy!"
Cardiff's Labour Assembly Members Vaughan Gething, Mark Drakeford, Julie Morgan and Jenny Rathbone called on the club's Malaysian owner Vincent Tan to "actively engage with the club's fan base and consult on these plans before destroying more than 100 years of history and tradition".
A spokesman for Cardiff City said the proposals were part of an annual review of the club which is due to be completed next week.
"We would like to assure supporters that any decisions will include the long term interests of our supporters, our community and the survival and development of Cardiff City Football Club in a highly competitive and modern sporting industry," a statement said.
"As a club we also appreciate the importance of our history, along with our position within the community.
"We fully recognise the legitimate interests of the fans, supporters and media in the affairs of the club and their right to information in respect of the same.
"On Tuesday we met with and held discussions with representatives from the local media, along with recognised supporter group and message board delegates.
"During these various meetings we discussed the various options going forward, all of which are to be ratified in upcoming board meetings as already mentioned.
"As such we will communicate any decisions made as quickly as possible, but it serves no interest to comment in depth at this time until those decisions have been taken."