The Coalition is preparing a sweeping policy pitch that combines a welfare crackdown on non-citizens with a major tax overhaul, as Opposition Leader Angus Taylor prepares to deliver his reply to Labor's federal budget on Thursday night.

Speaking to reporters in Canberra on Thursday morning, Taylor confirmed the Coalition would move to restrict access to a wide range of welfare payments to Australian citizens only, in a plan expected to save 'many billions' over coming years.

'If you are not an Australian citizen, then you don't get the privileges of an Australian citizen,' Taylor said.

'The simple principle is this: if you commit to this country, we'll commit to you.'

Under the proposal, 17 government programs, including paid parental leave and disability support through the NDIS, would be limited to citizens.

Existing recipients would be protected under grandfathering arrangements, but new arrivals would have to wait until they gained citizenship before accessing benefits.

'The NDIS would be restricted to Australian citizens. It'd be grandfathered for those who've already been on,' Taylor said, adding that migrants would still retain full access to Australia's healthcare system.

The Opposition is also tying migration levels directly to housing supply, arguing Labor's record intake, which peaked at 550,000 in 2023, intensified the housing crisis.

'Don't let more people in than you have houses to support, I would have thought that's common sense,' Taylor said.

He indicated migration would be cut sharply under a Coalition government, potentially to more than 70 per cent below Labor's peak levels, though final numbers would depend on housing availability.

'The net migration number will be set by the housing available … it should be capped by that,' he said.

The crackdown forms part of a broader Coalition push to redraw economic policy lines after what it has labelled a tax-heavy budget.

Treasurer Jim Chalmers' plan included billions in higher taxes on investments, trusts and capital gains, alongside the introduction of a $250-a-year Working Australians Tax Offset targeted at wage earners.

The Coalition has signalled it will back Labor's $250 Working Australians Tax Offset, while drawing a clear line against the government's proposed investment tax changes.

It will oppose the overhaul of negative gearing and the capital gains tax discount unveiled in this week's budget.

Under Labor's plan, investors would only be able to use negative gearing on newly built properties, tightening existing rules and targeting housing supply.

The government also moved to axe the 50 per cent capital gains tax discount across the board, including on shares, effectively winding the system back to its pre-1999 settings by linking it to inflation.

The Coalition argues these changes will hit investors, small business owners and startups, and has flagged it will fight to block them.

Chalmers has defended the approach as a long-term restructuring of the tax system.

'By introducing these changes, we're setting up a new architecture that, until now, has been absent from the Australian system,' he said on Wednesday.

'This will allow future tax relief and reform to build on these tax cuts and continue the work of rebalancing the tax burden so that it's shared more fairly between assets and labour.'

But the Coalition is planning its own tax overhaul, which would automatically increase tax brackets in line with inflation so workers are not pushed into higher tax rates simply because their wages rise during periods of high inflation.

The policy is designed to stop 'bracket creep' and provide Australians with ongoing tax relief over time.

'What you will see in our budget reply is the focus on getting rid of Labor's toxic taxes, taxes on homes, taxes on small businesses, taxes on hardworking Australians' savings,' Taylor said.