It comes amid concerns over funding at the group
The board of the Gay and Lesbian Equality Network (GLEN) has appointed Jillian van Turnhout to carry out a comprehensive review of the organisation.
It comes just a day after its chairperson, Kieran Rose, resigned.
The group is facing questions over funding and is potencially facing a review by the Charities Regulator.
The non-governmental organisation made a voluntary disclosure to the regulator amid queries over a number of issues.
These include the use of funds for non-GLEN political campaigns and the use of company credit cards for private purposes.
Concerns were brought to the attention of the regulator by the group's CEO, Áine Duggan.
Ms van Turnhout has a wide range of experience of governance of not-for-profit organisations.
She will begin her work on Monday April 24th, and report to the board within a period of six weeks.
GLEN say her initial work will focus on advising the board on corporate governance and compliance issues.
She will also advise the board on strategic decisions regarding the future of GLEN - as well as engaging with staff, stakeholders and board members before making recommendations.
The board has asked Ms van Turnhout to review compliance with Charities Regulations and advise on how to ensure compliance.
Separately, the board has engaged an independent financial consultant to review the organisation's financial administration.
The board welcomed her appointment, saying: "We are delighted that Jillian has agreed to act as a consultant and to work with the board at this time.
"We look forward to building on work which we had commenced in reforming corporate governance structures.
"GLEN has a proud history spanning three decades. In celebrating that legacy we also need to develop a strategy for the future."
Commenting on her appointment Ms van Turnhout said: "I am looking forward to working with GLEN and will do everything I can to assist the board.
"I hope my work will help ensure that GLEN is not only fully compliant with statutory obligations and corporate governance but also has a strategic vision."
Ms van Turnhout is currently vice chair of European Movement Ireland, chair of Early Childhood Ireland and director of the Irish Girl Guides Trust Corporation.
She is a former chief executive of the Children's Rights Alliance and a former independent Senator.