Funding for making solar panels in Australia is on the opposition's list of "unnecessary" spending and potentially on the chopping block if the coalition wins the next election.
Work was underway on a "credible alternative budget", opposition finance spokeswoman Jane Hume said on Sunday.
"The government has spent an additional $315 billion since coming to government that the coalition would not have committed to and didn't commit to back at the last election," she told ABC's Insiders.
"Some of that spending has been undisciplined and unnecessary."
Labor MP Andrew Charlton said the "$315 billion budget cut hit lists" would make medicines and energy more expensive and reduce the pension for older Australians.
"Under the Liberals, Australians will be working longer or less and many Australians will be made worse off," he told reporters.
Senator Hume promised there would be no cuts to essential services, including health, the aged pension or childcare.
Examples of "unnecessary" spending, in her view, included the $1 billion going into developing a local solar manufacturing industry and another half-billion for battery-making.
"There's plenty in the government's coffers that is unnecessary or undisciplined, so pushing inflation up further," Senator Hume said.
The opposition has also been critical of production tax credits, the centrepiece of government's Future Made in Australia plan.
Senator Hume said tax incentives would be going to critical mineral processing companies for work they were already doing.
She kept the door open for policies to support the industry, including more flexibility in the industrial relations system.
The opposition plans to review the federal government's suite of workplace reforms, with the senator confirming the 'same job same pay' laws would be included in that.
The laws ensure labour hire workers, commonly used in the mining industry, receive the same pay as permanent workers.
Senator Hume said the goal of the review was not to pay workers less but to "inject productivity back into the system".
"We all want higher pay but Philip Lowe, the previous Reserve Bank governor, and indeed this Reserve Bank governor, Michele Bullock, have reminded us that you simply cannot have wage rises without corresponding productivity growth," she said.
"Otherwise it's inflationary."
Employment and Workplace Relations Minister Murray Watt said her remarks "made it crystal clear that workers would be worse off if they were in power".
"Already (opposition leader) Peter Dutton has promised to scrap rights for casuals and the right to disconnect but today we learned he wants to go further," the minister said on Sunday.
