Tens of thousands of building workers are being sacked and replaced by cheaper ‘self-employed’ builders, the FNV Bouw union said on Thursday.

In two-thirds of cases, permanent staff were replaced by people on flexible contracts, union research quoted by the AD shows. And one-third of builders who lost their jobs told the union they had been offered a new, cheaper and temporary contract.

‘There are tens of thousands of flexible staff, including lots of Poles, Turks, Portuguese, Romanians, Bulgarians and Hungarians,’ FNV Bouw spokeswoman Mieke van Veldhuizen is quoted as saying. ‘Flexible workers in the construction industry… work in uncertainty and for far too little pay.’

The union estimates some 50,000 builders are currently unemployed and expects that to rise to 70,000 as the construction sector crisis continues.

The union questioned 1,500 builders, of whom 53% said their companies employed people who were ostensibly freelancers.

Parliament is due to discuss employment issues in the construction industry later on Thursday.