A report commissioned by the Charities Regulator into the financial affairs of Ataxia Ireland has found that inappropriate payments were made to the founding trustees of the charity.
The former trustees, who are the parents of the charity's CEO, were in receipt of payments totalling €84,000 between January 2008 and April 2016.
Inspectors found that the CEO did not inform the charity's other trustees about the payments, nor did the two trustees disclose the payments to the wider management committee that served between January 2014 and mid-2015.
Charity trustees are obliged to carry out their duties without payment other than reasonable out-of-pocket expenses.
The inspectors were not satisfied that the CEO's actions, in respect of the payments, were adequate to safeguard the interests of the charity.
The inspectors also found that there was a fundamental weakness in the financial management and control of the charity between 2014 and mid-June 2015.
Ataxia Ireland paid the employee pension contributions of the CEO (totalling approximately €38,500) and another staff member (totalling approximately €900) rather than deducting these payments from their salaries.
This began in July 2010 and was not identified until October 2016.
Ataxia Ireland has been given 21 days to respond to the Charities Regulator following the publication of the inspectors' report today.
"We have written to the charity trustees to instruct them that we require an action plan which addresses the inspectors' recommendations," Charities Regulator CEO John Farrelly said.
"If we are not satisfied with the response from the charity trustees we reserve the right to intervene under section 74 of the Charities Act 2009 to ensure the charity is protected."
Section 74 provides the Charities Regulator with the power to apply to the High Court for a range of measures to protect a charity.
This is the first inspectors' report to be published by the Charities Regulator since it was established in 2014.
Two other investigations are also being carried out by inspectors on behalf of the charities watchdog.
Ataxia Ireland is not commenting on the report.