Amateur boxing’s world governing body, Aiba, is planning to up the ante in its fight with the International Olympic Committee by filing a lawsuit if it is stripped of its right to run the sport in the run-up to Tokyo 2020, the Observer can reveal.

The extraordinary move, outlined in a private email by Aiba’s interim president, Mohamed Moustahsane, to his executive committee this week, comes as the IOC president, Thomas Bach, warned on Saturday that organising an Olympic qualifying tournament “is not rocket science, so I guess we will be able to manage it”.

It is the latest twist in Aiba’s acrimonious dispute with the IOC, which has spent six months investigating the sport. Insiders believe that the IOC is poised to take the unprecedented step of announcing that Aiba is impossible to work with in its current form when its executive board meets on 22 May – before stripping it of its right to run Olympic boxing.

Moustahsane’s letter, which was confirmed as authentic by senior figures in the sport, calls for an extraordinary executive meeting on 15 May and says the agenda will include a “vote on Aiba preparing a lawsuit on 23 May should the IOC decision regarding Aiba not be favourable”. It also confirms that a “vote on sending a brief complaint to the IOC ethics commission against some IOC members” is also on the agenda, as well plans to get its side of the story across.

Intriguingly, Moustahsane later sent out a second email telling his executive committee: “Please ignore the contents of this letter sent to you previously.”

However, Aiba confirmed that it could retaliate by instigating a lengthy battle in the Swiss courts if the IOC decision goes against it. “Aiba has fully addressed – and even exceeded – the demands from the IOC concerning governance, ethics, finances, anti-doping and refereeing and judging, despite being denied a right to a fair hearing for the past 18 months,” it said.

“[Aiba] will review all of its options, including legal, if the decision were to be negative, given that the IOC has breached the Olympic Charter.”