Opposition Leader Bill Shorten will use his budget reply speech to argue the Federal Government should maintain a temporary tax on high-income earners.

It is expected Mr Shorten will tonight declare the budget is "taxing middle class and working class Australians and spending it on millionaires and multinationals".

"This is the Liberal version of tax and spend," Mr Shorten will say in his speech.

Most Australians are set to pay more tax under the Government's budget plan to increase the Medicare levy by 0.5 per cent, to fully fund the NDIS.

Mr Shorten will instead promote what Labor sees as a fairer option: maintaining the Coalition's three-year budget repair levy, due to expire in July. The levy taxes people earning more than $180,000 a year.

"At a time when the Government is asking every other working Australian to pay a higher rate of tax, Labor will not support spending at least $1.2 billion each year on the wealthiest 2 per cent," he said.

The tax on the wealthy was introduced in the 2014 budget and designed to provide a $3.1 billion windfall.

Greens Leader Richard Di Natale agreed maintaining the deficit levy would be better than slugging lower earners.

"You have to actually bring in revenue in a way that's fair."

Neither Labor nor the Greens have ruled out supporting the Medicare levy increase.