Bill Shorten will trump the government's tax cuts for 2.9 million of the nation’s lowest paid but has ruled out adopting other cuts that would result in a flat rate of 30 per cent for the majority of  workers and benefit the highest paid.

Setting the scene for a tax stoush all the way though the election campaign, Mr Shorten will use his budget reply on Thursday to focus on people earning under $40,000, many of them women who do not fare so well under the tax package unveiled in Tuesday’s budget.