The value of federal government work outsourced to the big four consulting firms has crashed under Labor, with KPMG, EY, PwC and Deloitte inking just $607 million in new deals last year, the lowest level in five years.

That was down nearly 50 per cent from a peak of $1.2 billion in 2021-22, excluding extensions, with KPMG, EY and PwC all recording substantial revenue falls, which contributed to a wave of layoffs.