A dispute has broken out between the Irish Medical Organisation and its Director of Communications, Maria Murphy, who has been working at the doctors' association for 25 years.
Ms Murphy has been on sick leave since around June 2013.
She returned to work part-time on Monday, having been certified by an IMO doctor as medically fit to work part-time.
Ms Murphy had planned to work two days a week.
On Monday, after she arrived at the IMO, the organisation instructed her to leave the offices and not attend until various issues were resolved.
In correspondence with Ms Murphy, the IMO said that if she refused to leave voluntarily, steps would be taken to have her removed.
The IMO has also said it wants to finalise her terms and conditions of employment before returning to work.
Ms Murphy arrived again today for work at the IMO at 10 Fitzwilliam Place in Dublin, despite the direction from the organisation and she remains in the offices.
Ms Murphy, who is a member of the National Union of Journalists, is taking a case of alleged bullying against the IMO to the Labour Court.
The claims are strongly rejected by the IMO, which represents around 5,000 doctors.
A separate case alleging that the IMO has failed to pay her proper sick pay is also being taken.
Late last year, the Labour Relations Commission ruled that it did not have jurisdiction to deal with the sick pay claim.
The IMO had argued that the claim for around €64,000 was lodged a week late.
Ms Murphy worked with James Reilly when he was president of the union.
