Scott Morrison has sought to temper expectations for the personal income tax cuts in his third federal budget to be handed down on Tuesday.
"I'm not going to pretend these would be mammoth tax cuts, they will be what is affordable, they will be real and they will be within what the budget can afford," he told the Nine network on Sunday.
The treasurer said the government had flagged for many months the priority to deliver tax relief for low to middle-income earners because they had been doing it tough for some time without a decent pay rise.
Mr Morrison defended reducing taxes at a time when the budget was still in deficit saying surpluses were not built by taxing the economy.
"You've got to run a strong economy where people can be guaranteed the essential services they rely on and you need to have a responsible, methodical path back to budget balance which is what we have been doing, for five successive statements and it will be six on Tuesday night," he said.
A surplus has been forecast by mid-2021, which would be the first since before the 2008-2009 global financial crisis.
Shadow treasurer Chris Bowen said he wanted to see the tax system improved and made fairer.
"That's a key priority," he told ABC television.
"We also want to see budget responsibility. We will test the government's policies against those two yardsticks."
In the meantime, budget initiatives continued to roll out before the big night with confirmation the government would set up a tobacco taskforce to crack down on illicit trade.
The Australian Border Force will lead the taskforce while giving additional power to the Australian Taxation Office.
It is expected to raise $3.6 billion in revenue.
Finance Minister Mathias Cormann was confident they can raise that much.
"Based on all of the advice and all of the information in front of us that is the additional revenue number over a four year period," he told Sky News.
Health Minister Greg Hunt also made a trio of announcements.
The government is providing a $33.8 million cash injection into the mental health service Lifeline to boost its telephone service, while all pregnant woman in Australia will have access to a free whooping cough vaccination from July as a cost of $39.5 million.
Sufferers of spinal muscular atrophy will have access to a life-saving drug for a fraction of the cost.
Spinraza will be made available on the PBS from June 1 this year for all patients under 18.
It would have cost more than $367,850 a year for the medicine but it will now be $39.50 per script with concessional patients paying $6.40.
The government subsidies will cost the budget $241 million.