The EU-funded House of European History, a £47m museum celebrating the continent’s integration, has been accused of forcing contract staff to work seven days a week and ask for permission to drink water.

MEP Dennis De Jong has claimed that staff have endured bans on sitting, speaking or drinking during their 10-hour shifts looking after visitors.

“I think it’s a kind of slave labour,” De Jong said. “That’s what I call it, and mainly because I think it is an intimidating atmosphere. You set up such an expensive museum, and then you go for the cheapest solution when it comes to staff. It is humiliating for the people there.”

The complaints were passed to De Jong by a group of the staff who have been seeking to highlight their plight through a Twitter account called the Crew Support Campaign.

EU memorabilia. Photograph: Jennifer Rankin/The Guardian

One worker, interviewed by the Belgian newspaper De Morgen, said staff had initially been “allowed to take a bottle of water with us, but not later, because it was ‘too dangerous’”.

Staff were not allowed to talk unless in response to a “request for help or information”. Sitting was banned initially but the rule had been relaxed to prohibit it only in the “vicinity of visitors”.

“While we have to stand all day in our obligatory trainers, blue Pumas,” the worker said.

The MEP informed the European parliament’s authorities in September last year that the staff working for the agency Manpower were “obliged to work six or seven days, 10 hours a day”, and asked the chamber’s secretary general to examine whether Belgian labour law was being respected.

It was further claimed that workers “have been approached by Manpower, after blowing the whistle”, according to an European parliament report.

The parliamentary authorities responded that “the problems were created by too frequent absences of floor staff and insufficient replacements”, and that the museum’s management had “obliged the contractor to address the complaints of its staff”, according to an official report. It was claimed that Manpower had since “improved the quantity and duration of breaks”.

De Jong said he did not believe there had been significant improvements in the treatment of staff. “They have stools now but they are not allowed to sit on them if there are visitors. They are not allowed to talks to visitors accept to help them with the tablets they have to guide them around the museum. They are not allowed to bring bottles of water in and must ask permission when it is quiet to get a drink”.

The MEP said he had been told that the staff whose salaries start at €1,200 a month would at times work ten days at a go, due to the shift patterns. “And their only option is to quit of they don’t like it”.

The House of European History, in Leopold park, was the suggestion of Hans-Gert Pöttering, a former European parliament president who proposed the idea 11 years ago in order to “cultivate European unification and memory of European history”.

Eurosceptic critics including UKIP MEPs, however, have labelled the museum a “house of horrors” and “an expensive, wrong-headed palace of propaganda”. Some historians have also claimed that the goal of chronicling European history in one permanent exhibition is overambitious.

A spokesman for Manpower said: “Our expert guides in Brussels provide a valued service and we are committed to ensuring good working environments and complete transparency and fair pay for all of our people.

“When issues were raised in 2018, they were fully investigated and addressed to the satisfaction of the guides and our client. Our people are our priority and whenever workplace issues are raised by our representative employee group we carry out thorough consultations and investigation to address concerns in accordance with local legislation and our own high ethical standards.”