Concerned companies have highlighted the scale of the problem to the Enquirer as they point the finger at clients for forcing down tender prices.
One contractor said: “It’s ridiculous at the moment with some firms just blatantly buying work while clients go with them because all they are interested in is the lowest price.
“It’s surprising with public sector clients because they have spent the last few years talking about valuing quality over price.
“But it’s like that has been washed away overnight and all they see is the lowest price now budget cuts are starting to hit.”
Local authorities have already run into trouble after opting for the cheapest bid then watching their chosen contractors go bust.
Connaught and Rok undercut rivals across the country before their collapse.
And earlier this month St Alban’s council was left without a contractor for a £27m leisure centre after McNamara went under.
Rivals bidding against McNamara said the Irish firm’s bid was millions below all the others.
One contractor told the Enquirer: “We’ve gone for jobs recently and you get three or four firms in the same ballpark then someone who is more than 10% cheaper.
“Instead of that ringing alarm bells with clients, they are just going with the cheapest.
“It’s like we’ve learned nothing from the past or from what has already happened this time round with Connaught and Rok.”