A receiver has been appointed to Michael McNamara Construction, which was formerly owned by developer Bernard McNamara.
Receiver Farrell Grant Sparks was appointed yesterday.
Nobody from company headquarters would comment this morning and directed queries to FGS.
Sources close to the company have vigorously disputed NAMA's claim that the appointment of a receiver was agreed between the company and NAMA.
They said that if given three days' grace, they were optimistic that they would have been in a position to raise extra money.
They also said that as the receivers arrived, the building firm had received confirmation of a contract in the UK that would have been worth €45m.
Meanwhile, sources close to NAMA confirmed that the appointment of a statutory receiver to Michael McNamara Construction is the first use of NAMA's statutory enforcement powers.
They also said that NAMA had organised a tendering process for enforcement proceedings, and had negotiated a very competitive fee for the receivership with FGS in line with competitive rates emerging in the tender process.
It is understood that NAMA had recently rejected a business plan put forward by the company.
Michael McNamara Construction has offices in Dublin, Galway and Lisdoonvarna, Co Clare, and is currently involved in a number of construction projects around the country.
One subcontractor who spoke to RTÉ said the sites were closed yesterday evening.
Protests have been taking place at its building sites in Tallaght Institute of Technology in Dublin and at Letterkenny Hospital in Donegal.
Workers protesting at Tallaght claim they have not been paid for four months by McNamara Construction.
Up 40 people have been employed to extend the Synergy Building at the college since July of this year.