Áras an Uachtaráin has confirmed the departure of the most senior aide to President Michael D Higgins. Mary Van Lieshout, who was special adviser to Mr Higgins, left last month and has taken up a senior post with aid agency Goal.

The Áras has offered no explanation for Ms Van Lieshout’s departure. She did not respond to phone messages yesterday.

Mr Higgins’s spokesman said in a statement: “Mary van Lieshout moved from her post as adviser to the 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 RTÉ in March 2013."

Ms Van Lieshout took up her post in the Áras in February 2012. The President’s spokesman declined to specify the duration of her contract.

An informed source dismissed any suggestion that there had been tension between some of the President’s staff in recent times.

The spokesman cited the statement again when asked whether Mr Higgins was disappointed at Ms Van Lieshout’s move, saying the statement was clear in respect of her work.

Ms Van Lieshout has been appointed monitoring and evaluation adviser by Goal.

She was campaigns organiser and policy manager with Oxfam Ireland from 1989 to 1998, when she joined the former Eastern Health Board as health promotion officer.

Later she became head of research and standards development with the National Disability Authority, the independent agency that advises Government on disability policy.