Team GB captain Drew Sullivan has condemned Basketball Wales' "selfish and absurd" decision to break away from British Basketball after London 2012.
Britain were only given an Olympic spot on the proviso that Wales, England and Scotland would make a decision by 30 June about whether they would merge.
Sullivan told BBC Sport: "Whoever made the decision has a lot to answer for."
Basketball Wales said it made the call to benefit Welsh players, of whom none are included in the Games squad.
The organisation explained that it was rejecting the idea of a full merger based upon what was best for the game in Wales, and insisted that being part of a merged British organisation would restrict rather than enhance the international opportunities of Welsh players.
"Wales does not have any players participating in the GB team preparing for the 2012 Olympics," the statement said.
"The funding provided to British basketball to date has not devolved into Welsh basketball, and the participation of Basketball Wales in the BBF (British Basketball Federation) has not enhanced the game of basketball in Wales, including the numbers participating or the level and standard of participation.
"If Wales should abandon its status as an independent national member of FIBA, this opportunity would be lost to many participants in Wales who otherwise will experience international competition."
Wales' decision calls into question whether Britain will be allowed to compete at future Olympics.
Sullivan said: "British Basketball needs as few distractions as possible so to bring it up now is a little selfish."
"It's quite absurd that they have made this decision," Sullivan added. "You don't want to be the place that is hated from a basketball standpoint and unfortunately that's probably what's going to happen. A lot of people have put a lot of hard work in to get us to this point.
"The way forward for us, our future as a basketball nation, is to stay as Great Britain."
BBF chairman Bill McInnes admitted the news had not come as a surprise, even if they were unaware Basketball Wales had already taken their decision to world governing body Fiba.
Fiba general secretary Patrick Baumann said: "We are following closely the events in the UK and despite the negative Welsh opinion it is premature to jump to any conclusions about the future of the British Basketball Federation.
"We are first waiting to receive notification in due course of the decisions of England and Scotland and Fiba will then assess the future of the British Basketball Federation concept. In our view, this still remains the most sustainable opportunity of growth for all athletes in the UK and can lift the country to new heights."