Embattled Human Services and Veterans' Affairs Minister Stuart Robert is set to step down after a government investigation concluded he had breached the ministerial code of conduct in the course of a "private" visit to China.

Robert accompanied close friend and Liberal donor Paul Marks to China in 2014 in an ostensibly private capacity, where he attended a signing ceremony for one of Marks' companies and met with a Chinese minister. Robert is an investor in Marks' companies.