Union bosses have held crunch talks over strike action that could result in Ninewells Hospital grinding to a halt.
It has been claimed an administrative blunder has led to porters at the hospital being underpaid for the past 10 years.
Officials from the Unite union believe essential staff have been on a lower pay grade than colleagues at other hospitals across Tayside, and it wants staff compensated at an estimated cost of around £6 million.
NHS Tayside believes it has done nothing wrong and bosses are clear they will not give in to the union’s demands.
At a meeting on Tuesday night it detailed the findings of an investigation it believes exonerates it.
While the investigation has been taking place, Unite has balloted members on industrial action, with 86 out of the 105 members voting to strike.
An official announcement is expected later today.
Margaret Watt, chairwoman of the Scotland Patients’ Association, said: “This will have a big impact because porters are very important in hospitals.
“They take patients from one ward to another and they are very much needed. If they went on strike there would be nobody to do it.”
She urged Unite and NHS Tayside to keep talking until the matter is resolved without strike action as “the people who will suffer most will be the patients”.
The union’s regional organiser, Colin Coupar, said: “NHS Tayside have settled cases like this before but when it comes to this particular group, they are saying that everything is in order.
“It was only last year that we actually got the full details on the Ninewells porters, including the paperwork.
“We made a sensible approach to NHS Tayside, but they decided to have their own inquiries.
“We are now exploring legal routes and if there is one available to us then we will take it.”
NHS Tayside described the ballot action as “disappointing”, with director of human resources George Docherty saying it had come in the wake of a review that demonstrated no error had been made.
He said: “NHS Tayside is disappointed that this ballot for action has taken place when the review of the concerns raised by Unite the Union, involving a grading process designed and managed jointly with our trades unions including Unite has demonstrated that no error was made.
“Unite the Union raised an issue regarding the banding of porters under the Agenda for Change process some months ago.
“The grading of all posts is carried out by joint panels of management staff and trade union representatives working in partnership to agree the appropriate grade for a job description.
“This is a robust process in which trade union representatives are equal partners on the established panels and the process followed to agree the job descriptions for Band 1 porters was carried out jointly with our trades unions.”