Barnaby Joyce has unleashed on Labor's tax changes accusing the government of punishing Australians for building wealth and passing assets on to their children.

The former deputy prime minister clashed with Labor's Tanya Plibersek during a heated exchange on Sunrise after host Natalie Barr questioned the government's new tax changes.

As part of broader reforms to negative gearing and capital gains tax, the government will also introduce a minimum 30 per cent tax rate on certain family trusts from July 1, 2028.

The measure targets Testamentary Discretionary Trusts - a commonly used estate-planning structure that allows families to pass inherited wealth to beneficiaries after death.

Plibersek said the changes are designed to stop people using the trusts to shift income and assets in ways that reduce their tax bills.

Testamentary Fixed Trusts, however, will be exempt from the minimum tax and will keep their concessional tax treatment.

The main difference is that Testamentary Discretionary Trusts allow trustees flexibility to decide how income and assets are distributed among beneficiaries, while Testamentary Fixed Trusts set out each beneficiary's share in advance under the terms of a will.

'Testamentary trusts are trusts that you set up to distribute money to your kids after you've died,' Plibersek said.

'You can either distribute that money in set shares to your children, or you can have someone else deciding that this kid gets more this year, this kid gets less this year.

'What we're saying is if the share is fixed, no change, that's fine. If you're able to shift the money around, you might be doing that to minimise tax.

'So that's going to have the minimum 30 per cent tax attached to it.'

'Isn't that a death tax, Tanya?' Sunrise host Natalie Barr asked the Labor MP at one point.

'No, it's not because you can still have a fixed testamentary trust if you want to,' Ms Plibersek replied.

'People who work for a living should not get taxed more on their wages than people who are living on their assets,' Plibersek said.

Joyce accused Plibersek of misleading Australians about the impact of the changes.

'No one believes you, Tanya,' Joyce said.

Shaking his head, Joyce then launched into a broader criticism of the reforms.

'It's their wages. It's socialist. They've already paid tax,' he said.

Joyce argued many Australians deliberately choose to save and invest for future generations rather than spend money on themselves.

'They buy their assets because they don't throw the money up against the wall,' he said.

'They say, rather than go on a trip, I'm going to buy this asset to make my kids happier after I die.'

He then accused the government of undermining families' ability to pass on wealth.

'But you say, no, we can't do that. You've got to give it to Uncle Jim,' Joyce said.