Management at St James' Hospital in Dublin say staff can park in the nearby Kilmainham Hospital.
St James's is being criticised today after removing 300 parking spaces from their grounds to allow the new National Children's Hospital to be built.
Hospital workers claim that their security is being compromised by the move.
However, management say a full-time Mobility Manager has been in place for the last year to assist staff in planning their journeys to and from work.
Industrial Relations Officer with the INMO nurses union Clare Tracey says they need more time to adapt.
Ms Tracey said: "There are nurses and others who are used to having a car parking space and who require it for safe access.
"People have conditioned their lives around their work, so they may be dropping kids off, they may be doing various other things.
"If there is going to be change, there needs to be time to introduce that change."