Patients who go to State Government-run hospitals with minor ailments will be stung with a $7.50 co-payment under an Abbott Government Budget plan to ensure no one escapes the so-called GP tax.

The new impost means triage doctors and nurses in emergency departments will have to decide who can see a doctor free and who will have to pay.

Federal Government insiders said expanding the co-payment to State hospitals was necessary to prevent patients dodging a looming $7.50 charge on bulk-billed GP visits and other Medicare services.

But it will require the Commonwealth-State healthcare agreements to be rewritten and development of a specific code on what constitutes a health emergency.

Treasurer Joe Hockey yesterday said the purpose of the co-payment was to build a stronger health system.

"There is no ideological commitment to ask people to contribute," he said.

"And if we don't all contribute to the sustainability of our quality of life, we are going to leave our children with a lesser quality of life than we have."

Australian College for Emergency Medicine WA faculty chairman Dave Mountain said the emergency department co-payment was an "incredibly dumb piece of public health policy" and predicted doctors would refuse to collect it.

Dr Mountain, the immediate past president of the AMA in WA, said sections of society vulnerable to bad health, including the poor, the elderly and Aboriginal people, would be dissuaded from keeping on top of chronic diseases and end up at emergency departments in a worse state.

"It is more likely to discourage somebody who actually needs care and ongoing attention from seeking it than discourage people who are abusing the system," he said.

Labor leader Bill Shorten said the quality of health care "should not depend upon your credit card but your Medicare card".

"You should go to the doctor if you are sick and you should not avoid going to the doctor because you are poor. Universal Medicare is one of the things that distinguishes Australia from America," he said.

_The West Australian _understands that the Department of Finance told the coalition that under the spending trajectory left by Labor, Government outlays would increase a massive 7 per cent in one year, between 2016-17 and 2017-18. With a view to recording a surplus within the next five years, tomorrow's Budget will include broad tightening of welfare eligibility that will cost some families thousands of dollars a year. Disability pensioners under 35 will have their fitness for work reviewed and school leavers will be denied immediate access to the dole.

There will be a 2 per cent deficit levy on incomes of more than $180,000 and fuel excise will be indexed six-monthly.

Mr Hockey insisted these measures did not breach Prime Minister Tony Abbott's pre-election pledge not to increase taxes.

"We never said that we were never going to, never change a tax, or alter a tax," Mr Hockey told the Nine Network.

More than $470 million will be saved by dumping or amalgamating 36 government agencies.

A supersized review body will be formed to include the Administrative Appeals Tribunal, the Classification Review Board, Migration Review Tribunal, Refugees Review Tribunal and Social Security Appeals Tribunal.