Shadow treasurer Chris Bowen has promised a Labor government will examine the case for personal income tax cuts when the budget is in surplus.
In his budget reply speech to the National Press Club on Wednesday, he will take Scott Morrison to task over his aim to lower personal income tax when he became treasurer.
"On multiple occasions, he told us he wanted large, swingeing tax cuts," Mr Bowen will say.
"Eventually, he delivered modest tax cuts last year. And took them back this year."
The modest changes to personal taxes in 2016 cost the budget $4 billion, while this year's increases will raise $8 billion.
"I'd hate to see what the treasurer would do if he actually thought Australia had a revenue problem," Mr Bowen will say.
He says you have to go back to the Gillard Labor government to find a time when lower-income workers had a tax cut.
This is at a time when wages growth is at a record low, penalty rates are being reduced - an unprecedented pay cut in the postwar era in Australia.
"When the budget is in surplus, personal income tax relief can be examined," he will say.
In his prepared speech, he says virtually every key economic parameter has "collapsed" since the budget a year ago with economic growth down, wages down, employment down and the unemployment rate up.
"These figures don't give us reason for optimism and yet (last week's) budget also continues to include unrealistic forecasts which help the return to surplus."
Wages growth is forecast to double to 3.75 per cent by mid-2021.
"A pretty big bounce given the spare capacity and record underemployment we are currently seeing in the labour market, together with the cut in penalty rates and the fact the budget papers show the unemployment rate isn't expected to fall that much," Mr Bowen will say.
