The union of supporters is the latest development in the bitter fan war with the FFA, led by Western Sydney Wanderers' Red and Black Bloc, Sydney FC's The Cove and North Terrace of Melbourne Victory. The three largest supporter groups will be joined by supporters of the seven other A-League clubs who are travelling from as far as New Zealand and Perth to attend the meeting. Fairfax Media understands the meeting was arranged by, and some travel costs covered by, a third party – in conjunction with some clubs.

United we stand: Supporter groups will come together in Sydney to discuss their plan of action. Credit:Getty Images

Representatives of all 10 groups were in regular dialogue last week and drafted a Memorandum of Understanding that will be presented to the FFA. The consortium is understood to be in agreement with most clauses of the MOU, which will be finalised at the extraordinary meeting in Sydney.

The overriding issue for fans is the absence of an appeals process for innocent fans who have received bans and the lack of transparency provided by the FFA to banned supporters. A-League fans claim there is no presumption of innocence provided to spectators by police, the FFA and security firms and are critical of the FFA's reluctance to publicly defend the reputation of members despite praising the atmosphere they create at games.

Over the past fortnight, News Corp columnists labelled them "suburban terrorists", NSW Police called fans "grubs" and radio commentator Alan Jones likened the situation to the Paris terrorist attacks.