Wu Ching-kuo’s controversial 11-year reign at the top of amateur boxing’s governing body, Aiba, looks to be drawing to a close after an overwhelming number of the sport’s biggest nations and federations indicated they backed the president’s opponents in the bitter power struggle that has rocked the sport.

Wu, who has been accused of “financial mismanagement” and “collecting substantial funds from Aiba for personal use in his Taipei office” by those trying to depose him, will learn his fate an extraordinary congress in Dubai in November.

The 70-year-old, who last month also suffered a vote of no confidence in him by his own executive committee in Moscow, needs the support of the majority of the Aiba federations that show up in Dubai to survive. However, the Guardian has seen letters from 76 federations, including the US, Cuba, Russia and Kazakhstan, saying they all back Aiba’s interim management committee (IMC) in their fight against Wu.

That could be decisive, given only 126 of the 201 nations affiliated to Aiba turned up for its last congress in December.

A letter from the president of the French Boxing Federation, André Martin, is typical. After expressing his full support for Wu’s rivals, he adds: “I am deeply convinced that the IMC are able to put our beloved organisation back on track. You can count on my unconditional support and the support of the French Boxing Federation.”

Meanwhile, the Board of Boxing Australia says it “views with great concern the current poor financial position which Aiba appears to be in, and the apparent role played by president CK Wu in precipitating that poor position” before adding that it “supports the actions taken by theexecutive committee of Aiba at its recent meeting in Moscow.”

Wu is under pressure from a number of fronts, with the Azerbaijani company Benkons demanding he pay back a $10m loan by Monday or face legal action.

In a letter seen by the Guardian, it warns Wu that if Aiba does not pay up “we will be forced to take the appropriate next steps, including a legal action in Swiss courts to recover our loan.”

Wu has always insisted that Aiba’s finances are on a sure footing. However, during Aiba’s executive committee meeting in Moscow last month auditors from KPMG told Wu and other committee members that Aiba has negative unrestricted funds of 15m Swiss francs. That is a deterioration from last year and they cited Benkons’ demand, the poor performance of World Series of Boxing, plus legal and compliance costs, as being significant challenges to its financial outlook.

Separately, the Swiss courts are expected to rule on Thursday whether it is Wu or the IMC who has the right to run Aiba until the extraordinary congress in November. Wu has dismissed the right of the IMC to exist, saying it “has no legal foundation”. However, the IMC says Aiba’s statutes allow them to run boxing, given the circumstances the sport finds itself in.

Wu has always denied any wrongdoing, financial or otherwise, and says he needs the 200,000 Swiss francs he gets each year for his office because he is a volunteer who travels more than 200 days a year representing Aiba.