Civil Service pensioners have branded a deal on equal pay "morally indefensible".
The Civil Service Pensioners' Alliance wants retired members of the public service to be fully compensated after changes saw serving administrative staff paid more.
In 2009 a settlement was reached with the Department of Finance to raise the salaries paid to mainly junior administrative staff because the quality of their work matched that of some technical grades which were paid more.
Ivan Baxter, Northern Ireland secretary of the Alliance, said: "As it stands, this settlement is unfair, unreasonable and morally indefensible."
Following the deal the salaries of serving staff were improved and compensation paid to those still in work for loss of earnings backdated to February 2003. However, nothing was paid to staff who retired between then and August last year unless they lodged a claim for equal pay within six months of retiring.
Members of the Alliance, Age Sector Platform and retired members from the Northern Ireland Public Service Alliance are meeting the Finance Committee at Stormont.
They estimate 460 people require compensation.