Kieran Hartley, the Fianna Fáil MEP substitute for Brian Crowley in Ireland South, has complained to party leader Micheál Martin that Mr Crowley has not attended the European Parliament since he was re-elected in 2014.
Mr Crowley, who was left paralysed from the waist down after an accident as a teenager and uses a wheelchair, has suffered from ill-health in recent years.
European Parliament records show Mr Crowley has not been present for any votes since 2014, and his office confirmed he has not attended the parliament in recent years due to ill-health and a lengthy period of hospitalisation.
His office said he was “working away from hospital”.
When he leaves hospital, his spokesman said, Mr Crowley intends to answer “any and all issues”. However, he was unable to supply a date for Mr Crowley’s departure from hospital. “We don’t have a hard timescale on when we expect him out,” he said.
Under European Parliament rules, if an MEP steps down, instead of a byelection, the substitute automatically becomes the MEP.
Mr Hartley has written to the Fianna Fáil leader three times in recent months to draw his attention to Mr Crowley’s ongoing absence from the European Parliament.
In his most recent letter, Mr Hartley said Mr Crowley’s ongoing absence meant Fianna Fail had no representation in the European Parliament.
This, he said, meant Fianna Fáil “struggles with credibility on the Brexit issue with zero European parliament representation”.
Mr Hartley demanded that Mr Martin now address the issue.
Mr Crowley left the Fianna Fáil Parliamentary Party when Fianna Fáil joined the ALDE (Alliance of Liberals and Democrats for Europe) ) group of liberals in the parliament, but he remains a member of the party.
Mr Crowley joined the ECR (European Conservatives and Reformists) group of conservatives and reformists, which includes the British Conservatives and other eurosceptic MEPs.
In a statement, a spokesman for Mr Martin said the party “would not comment on private correspondence” concerning Mr Crowley.
“While he is currently in ill-health, we understand that his office continues to provide a full range of services to constituents. We wish Brian a full and speedy recovery,” the spokesman said.