"The minister went in on his bike one morning. He stopped to look at us and went on his way again," says Breda Murphy, one of 13 cleaners picketing the Department of the Environment's offices in Dublin's Custom House.

The picket by 12 cleaners and their supervisor – 10 women and three men – began on 1 July after the contract for cleaning services in the landmark Gandon-designed Custom House changed hands.

When the new service provider, Schorman Contract Cleaning Services Ltd, informed existing cleaning personnel they intended reducing their working hours, Siptu's contract services branch wrote to the company that its members' jobs were protected under the European Communities (Safeguarding of Employees Rights under the Transfer of Undertakings) Regulations 2003.

On 23 June, Schorman sent another letter to the cleaners, this time informing them it was terminating their employment at the Custom House from 1 July.

"My personal thinking is they didn't want the union involved," said Breda Murphy (60), from Dolphin's Barn, who has been cleaning the Custom House for five years. "I'm a bit disappointed because it was the Custom House that gave out the contract."

A spokesman for environment minister and Green Party leader John Gormley said the awarding of the cleaning contract was not part of his remit. He added that while the minister is opposed to contracts for staff in the Custom House, EU tendering rules must be adhered to and the matter is an industrial-relations issue.

"The department has attempted to facilitate an engagement between the parties to find a resolution through the Labour Relations Commission," the spokesman said. However, exploratory talks at the LRC last Wednesday came to naught and the following morning nearly 200 Siptu officials picketed the Custom House in solidarity with the cleaners.

Murphy, who earned €190-a-week for her four-hour-a-day work, says she is depending on that money to meet her mortgage repayments. "My husband only works three days a week on a back-to-work scheme. We're both low-paid workers and we need the two incomes to keep our home," she said.

Last year, when a company that previously employed Murphy for cleaning the Custom House went into liquidation, the service provider appointed in its place, ECO Facilities Management Limited, honoured the terms and conditions of existing personnel.

The cleaning contract came up for tender last November and it was announced in May that it had been won by Schorman.