Opposition Leader Bill Shorten will insist that workers on low and middle incomes are the biggest winners from any personal tax cuts in next week’s budget, as he sets a key test to ensure the changes gain swift approval in Parliament.

Mr Shorten will argue that the tax relief can deliver the strongest economic boost if it is targeted to those on the lowest incomes, guaranteeing the money will flow to consumer spending rather than being saved by those in wealthier households.

The Labor leader's position makes it clear there is room for a negotiation with the government on the personal income tax cuts despite warnings from Deloitte Access Economics director Chris Richardson and other economists about the need to shore up the budget bottom line.

In an exclusive interview with Fairfax Media, the Opposition Leader also signalled a halt to Labor’s mammoth revenue increases after the $55.7 billion reform to dividend imputation announced in March.

“Those hard decisions, which cost us a bit politically, mean we’re in a position to fund our promises and still be responsible fiscally and tackle debt,” he said.