By Gordon Farquhar
BBC Five Live sports news correspondent
Olympic chief Jacques Rogge is under pressure over a vote to decide which of 28 sports to drop for the 2012 Games.
Greco-Roman wrestling is one of the sports thought to be in danger
Rogge wants to include new sports such as rugby union, squash and karate - but does not want to expand the Games.
The heads of the 28 existing sports federations have now called an emergency meeting over the scheme.
A petition opposing plans to put the inclusion of each sport to a free vote at a meeting in July is understood to have been signed by 12 of them.
The International Olympic Committee has been wrestling with this problem for some time, and is now facing what could lead to a rebellion by some of the Olympic sports.
Under the plans announced last week, all 28 sports will need a straight majority from the voting members to stay on the programme: any who fall short will be removed.
Baseball, Softball and Modern Pentathlon are thought to be most vulnerable, having previously been singled out for possible removal from the games.
The Federations are not happy, with some heads critical of IOC President Rogge's handling of the matter.
They will meet in Geneva in June to decide what to do next.