Fletcher Building has told investors it is facing a range of new threats from overseas companies importing cheaper products into New Zealand.
It says new import-based competition is emerging particularly in cement, insulation and steel - and that may increase as the rebuild gets underway in Christchurch.
Fletcher Building chief executive Jonathan Ling says the rivals are just minor players at the moment, but they are able to offer lower prices due to the high New Zealand dollar.
Mr Ling says it is easy for new entrants to make special offers but, ultimately, unsustainable. The industry is at an almost all-time low, so prices are already competitive.
Fletcher Building has invested heavily in Christchurch in order to stay competitive, he says.