Adviser 'unhappy over role of President's assistant'
Mr Higgins got the wage cap lifted last year in order to pay the highly regarded aide a salary of €103,000.
But just half way through her contract, Mary van Lieshout has left amid reports of tensions among Mr Higgins's most trusted aides.
The controversy over the former third world aid worker's departure comes just a week after it was announced that Mr Higgins will make a historic state visit to Britain next April.
The growing influence of Mr Higgins's executive assistant Kevin McCarthy, a more junior staff member who it has been suggested has better access to the President, was reported yesterday in the media to be central to tensions in the Aras.
Mr McCarthy worked as Mr Higgins's driver during the presidential election campaign. The 33-year-old was appointed to the specially created position of executive assistant when Mr Higgins took office in November 2011.
Earlier this year, the Irish Independent reported that Mr McCarthy accompanied Mr Higgins on a holiday in Lanzarote to work for the President.
It is understood Ms van Lieshout was unhappy with the level of access to Mr Higgins she was afforded on a day-to-day basis in the Aras.
The American-born adviser has known Mr Higgins since the 1980s and was personally approached by the President to become his chief aide, but she had never actually worked with him before.
She took up the position in February 2012, with the Aras breaching the salary cap of €80,000 to bring her into the role.
place where Mary did not knowing him very well, building it from zero, it's difficult," an informed source said.
"You have to have the working relationship built up beforehand," the source added.
Ms Van Lieshout has now taken up a position with the aid agency, Goal, as its head of research and education.
A statement from the Aras played down the controversy, saying Ms Van Lieshout made an "excellent, and valued, contribution to the overall work of the Presidency".
Mr Higgins will be appointing a successor, with an announcement to be made "in due course".
"Mary van Lieshout moved from her post as Adviser to President in October to pursue other interests and has since taken up an appointment in the NGO sector. Mary made an excellent, and valued, contribution to the overall work of the Presidency, especially on the Being Young and Irish initiative and the Glaoch production, in conjunction with RTE in March 2013," the statement said.
At her home in Dun Laoghaire, her husband said she would not be commenting and referred queries on the matter to the Aras.
"We will not be providing any comment or making any remarks about previous reports," he told the Irish Independent.
Sources close to the Aras, meanwhile, moved to dampen growing speculation that Ms van Lieshout had left after becoming increasingly frustrated about the structures in place.
A source said there were no "difficulties" among the staff of the Aras regarding access to President Higgins.
"There is no basis for the main contention of this report. Meetings are arranged through the Mr Higgins's private secretary not through Mr McCarthy, and no one has any difficulties in relation to access to the President," a source said.
However, the Aras is declining to comment on claims that Ms Van Lieshout was required to go through Mr McCarthy to gain access to Mr Higgins.
Mr McCarthy is a former personal assistant to Labour Party TD Michael McCarthy. He knew Mr Higgins from his time working as a personal assistant to the Labour TD.
Ms van Lieshout is described as a long-time admirer of Mr Higgins's work, having first met him in Cambodia in the 1980s. She met her husband in Zimbabwe in 1986 and the couple moved to Ireland as he is from Dublin.
The former humanitarian aid worker has a MSc in Community Health from Trinity College and an MA in International Relations from Dublin City University.