Federal Labor has used its budget reply to offer a bigger tax break than the Government.

Key points: Labor promises personal income tax nearly double that of the Government's

Labor promises personal income tax nearly double that of the Government's Outspends Government on health and education

Outspends Government on health and education Challenges Government to campaign on the budget during byelections

Labor leader Bill Shorten has promised to introduce a Working Australians Tax Refund at a cost of nearly $6 billion over four years.

He told Parliament it would mean more money for 10 million people.

He said 4 million people would get the full benefit of $928 a year, which is $400 more than the Government is offering.

Mr Shorten attacked the Government's plan for big tax changes from 2024-25.

"How can it be fair for a carer on $40,000 to pay the same tax rate as a doctor on $200,000? For a cleaner to pay the same tax rate as a CEO?"

Mr Shorten pointed to research released yesterday showing that 60 per cent of the benefit of the plan would go to the wealthiest 20 per cent of Australians.

"Very quickly, this is starting to look like a mate's rates tax plan from the Liberal Party," he said.

He attacked the Government's handling of the nation's finances, saying too many jobseekers are stuck in poverty, and women fleeing family violence cannot find safe accommodation.

Mr Shorten said Labor would — as it has foreshadowed — back the first tranche of the Government's tax plan which is due to kick in from July.

He promised his higher refund would start from the following tax year.

The Coalition was quick to hit back at Mr Shorten's alternative budget, with Finance Minister Mathias Cormann leading the charge.

"His numbers don't add up, you can't trust a single word Bill Shorten says," Senator Cormann said.

"Bill Shorten puts things out there without any details without any proper costings if he was so serious he should release the Parliamentary Budget Office costings.

"We've released our budget, all of our costings went through Treasury and Finance."

Senator Cormann suggested those costings should be delivered before a suite of by-elections across the country, due in the next few months.

$2.8 billion for hospitals, blocking $80 billion tax cuts

With five by-elections due soon and a federal poll within 12 months, Mr Shorten has used his budget reply speech to kickstart Labor's campaign.

He challenged the Prime Minister to fight the by-elections on the budget.

"If you think that your budget is fair, if you think that your sneaky cuts can survive scrutiny, put it to the test," he said.

Sorry, this video has expired Leigh Sales interviews Bill Shorten after his budget reply speech ( Leigh Sales )

As well as the bigger tax cut, Mr Shorten has focused on traditional Labor territory of health and education.

He has promised $2.8 billion extra money for hospitals, which he said would completely reverse the Coalition's cuts.

Mr Shorten said that money would help reduce emergency department and elective surgery waiting times and provide more beds, doctors and nurses.

He also targeted the cost blowouts in vocational education, with a promise to scrap upfront fees for 100,000 TAFE students and to spend $100 million modernising TAFES around the country.

His budget reply speech promised about 200,000 extra places at universities over 12 years.

"We believe that everyone with ability and dedication should get the chance to study at uni," Mr Shorten said.

He did not give a costing for the extra university places.

Mr Shorten said he can afford the extra spending because he would not spend $80 billion on big business tax cuts.

Sorry, this video has expired Bill Shorten attacks Government's $10 tax cut

He dismissed the Government's planned tax cut as too small and unfair.

"$10 a week, that is all that the Liberals think it will take for you to forgive and forget," he said.

Mr Shorten said the Government was assuming "that for $10 you won't mind if your internet's no good or your local TAFE is closing".

"This Prime Minister is so out of touch he thinks if you get $10 a week you will be fine with the banks getting a $17 billion giveaway," Mr Shorten said.

Christopher Pyne, Julie Bishop and Scott Morrison looking at their phones during Bill Shorten's speech. ( ABC News: Matt Robers )

He slammed the Government over one of the key elements of Tuesday's budget, calling the aged care package a fraud.

"Around 105,000 older Australians are waiting for home care packages, but despite all the hype, the Government is offering only 14,000 places over the next four years," he said.

Mr Shorten said 20,000 people joined the waiting list in the last six months.

And he noted the Government maintained its policy to lift the pension age to 70.

He lambasted the Government for cutting funds to AISC as a "disgrace" and "immoral" and pledged a $25 million taskforce for public prosecutors to follow up on the work of the banking royal commission.