Andrew Scadding, chief executive of the Pattaya Orphanage Trust, said the FSB was wrong to describe itself as a self-regulatory organisation because members cannot elect its board.
The FSB's memorandum and articles of association prohibit member charities from voting at general meetings, including those to elect the board.
The governing document also prevents members from being elected to the board to adjudicate on fundraising complaints.
Scadding said these rules left FSB members with a diminished say. "Self-regulation implies the participation of the regulated in the regulatory body," he said. "When independence extends beyond the complaints process and into actual governance, the meaning of self-regulation is stretched to the limits of credibility.
"For the fundraising community to be permanently constitutionally excluded from that process seems almost a guarantee of failure and unfairness."
Adrian Sargeant, professor of philanthropy at Indiana University, said that charities were paying subscription fees, so they ought to have a say.
"It will, after all, be fundraisers who have to justify to their donors their future expenditure in this area," he said. "The current set-up gives scope for the creation of a potentially very expensive bureaucracy."
Bridget Hutter, professor of risk regulation at the London School of Economics, said she was surprised the FSB did not allow fundraisers on its ruling panel.
"Having practitioners on a self-regulatory board helps with legitimacy," she said. "Often they are the most critical of others not adhering to codes of practice."
The FSB board includes representatives from the Institute of Fundraising, the Public Fundraising Regulatory Association, the Scottish Council for Voluntary Action, the Wales Council for Voluntary Action, a lawyer and five lay members.
In a statement, the FSB said it was following best practice by appointing independent representatives in order to avoid conflicts of interest.
It said its members and potential members had been given "ample opportunity" to influence and shape the self-regulatory body during the consultation process.