Annual economic growth has slowed below 2 per cent for the first time since the global financial crisis amid a collapse in government spending, weak business investment and falling home construction.

In the worst result since the depths of the 2008 crisis, gross domestic product fell 0.5 per cent from the June quarter, when it rose by a revised 0.6 per cent from a previously reported 0.5 per cent, the Australian Bureau of Statistics said on Wednesday.