The closure of steelmaker Arrium would cause Australia's construction industry to collapse within six weeks, its administrator says.

“The impact would be felt far and wide. Arrium long-form structural steel makes up 70 per cent of Australian steel making in infrastructure and construction,” KordaMentha’s Mark Mentha said. “When you’re talking about billion-dollar projects, delivery for steel would be 18 months or more in advance. The impact of not…