Shorten must explain $200b tax grab: PM

Bill Shorten says a future Labor budget will put workers and the middle class ahead of big business

Malcolm Turnbull has demanded Labor leader Bill Shorten use his budget reply speech to explain how ripping $200 billion out the economy won't send the country backwards.

The opposition leader will outline a financial strategy that will look after battlers instead of big business when he responds to the federal budget in parliament on Thursday evening.

Mr Shorten has a war chest to spend thanks to his proposed changes to a range of tax measures, including negative gearing, dividend imputation and capital gains tax.

"When Shorten stands up tonight and talks about his plan for the budget he's got to explain how ripping $200 billion-plus out of additional tax out of the Australian economy is not going to do anything other than inflict real hardship on hard-working Australians," Mr Turnbull told reporters in Queanbeyan, NSW.

But deputy opposition leader Tanya Plibersek predicts voters will see a "real Labor vision" for the country.

"Tonight you'll see an alternate vision for Australia that emphasises greater support for the vast bulk of people - low and middle-income earners," she told reporters in Canberra.

Mr Shorten will back the coalition's tax cuts for low- and middle-income earners set to come into effect on July 1, but won't back other proposed changes out to 2024/25.

He will also stick to his guns in opposing further corporate tax cuts.

Treasurer Scott Morrison insists the three phases of his seven-year personal income tax plan are one package.

Mr Turnbull said the government's "huge reform" meant someone earning $200,000 would still pay 12.5 times more income tax than someone on $41,000.

"What we're saying is that hardworking Australian families, particularly middle-income Australian families deserve to keep more of the money they earn - it is their money," he said.

The bulk of Australians - 94 per cent - would not get "slugged" by going into a higher tax bracket if they won a promotion or worked overtime.