The Construction Industry Federation has warned that the cost to building firms of the crane operators' dispute is mounting.

Crane drivers who are members of the Unite union took part in strike action over pay that halted operations on many construction sites nationwide.

The CIF said that based on a sample of ten sites involving projects worth €5 billion, the daily value of lost turnover is €1.4 million.

While there's a saving on wages of €130,000 per strike day, some costs like leasing machinery or subcontractors not used cannot be recovered.

There is also a risk of €1.2m in penalty payments for missing deadlines.

Earlier, CIF Director General Tom Parlon accused Unite of holding 'Ireland Inc' to ransom in pursuit of an unsustainable pay claim.

The dispute is further complicated by an inter-union row with SIPTU, which has traditionally represented crane drivers.