Staff at the National Museum of Scotland may strike because visitor assistants are forced to stand for hours, which they claim leads to health problems.
The Public and Commercial Services union said workers at Scotland’s flagship museum are being “bullied” by being refused designated seats.
Seats are allowed for staff at attractions such as the Scottish National Portrait Gallery and the Scottish National Gallery in the capital.
Union officials said most museums in major European capital cities, including the British Museum in London, also allowed assistants who spend long periods standing to have their own seating areas.
The dispute comes after the museum was hit by a wave of strikes about the withdrawal of weekend working allowances for the attraction’s lowest-paid employees.
Robert Burns, a PCS representative for Edinburgh’s museum workers, said he had suffered ligament damage by effectively being made to stand for hours on a hard floor at the museum.
He confirmed a ballot on industrial action could take place in the new year over possible strikes at Easter, one of the busiest periods of the year for the museum.
He said about 70 workers would now decide whether to have the ballot, which could involve one-day stoppages or action short of full strikes, such as a work to rule.
Burns said staff had repeatedly been refused designated seats, but told they could use the public seating area, something he said workers felt uncomfortable about doing while they are on duty.
He added management could easily agree to the union request and give staff the same deal as those at other state-run visitor attractions.
He said: “Staff are being told they can’t have a seat unless they sit in public seating, which people are uncomfortable with as they are getting on with their work.
“But the management has said it won’t provide designated staff seating.
“It’s low-level bullying from management as this is something that they could easily provide but won’t even though some staff are suffering with aches and pains.”
“I once tore a ligament and I know staff who have had back pain. Having to stand for six hours on end for five days is a long time and people are really feeling it.”
A PCS Scotland spokesperson called on National Museums Scotland to agree to the staff seating request.
The union spokesperson added: “This is a reasonable request and our members are frustrated at the intransigence of management.
“We now hope that management will act to resolve this issue quickly.”
Labour MSP Neil Findlay has accused the management of “confrontational” behaviour towards the union and warned the reputation of one of Scotland’s most popular museums could be damaged by the treatment of its workers.
The Lothian MSP echoed the PCS’s call and added: “The National Museum of Scotland is one of our key cultural attractions in Scotland.
“In recent years the management have taken a confrontational line in their dealings with trades unions there representing employees, first over weekend allowances and now over working conditions.
“The management really need to think again about the way they are conducting industrial relations otherwise the reputation of the museum will suffer.”
Julie Matthews, head of visitor experience at National Museums Scotland, said management had a constructive relationship with the union.
She said: “The role of visitor experience assistant is an active one in which staff move around the museum to welcome and engage with our visitors.
“However, staff have access to seating throughout the galleries and anyone with additional needs is supported on an individual basis.”