The Morrison government has proposed disqualifying company directors and banning businesses from using visa workers to deter underpayments, as it also pledges "significant" jail terms and fines for the most serious cases.

Industrial Relations Minister Christian Porter confirmed he would introduce the government's wage theft bill "in the coming weeks" as he released two new reform papers on Tuesday that propose further civil sanctions for underpayments, as well as expanded restrictions on union behaviour in the construction industry.