The managing director of one of the country’s biggest construction groups says multibillion-dollar infrastructure projects are coming unstuck because international contractors are underbidding for work and don’t properly understand the cost of local materials and labour.

“Everyone comes here, and they think they’ll bring their knowledge and how they do it overseas to here, and it will be straightforward,” CPB Contractors’ managing director Jason Spears said. “Then they work out the hard way how much things cost in Australia and how regulated Australia is.”