Queensland senator Matt Canavan has clashed with Greens leader Larissa Waters over Labor’s super tax plan, saying he will “fight to the death” to oppose it.

Canavan and Waters clashed on breakfast TV on Wednesday over the government’s plan to double the tax on superannuation balances above $3 million.

“There’s no way in hell we’ll support attacks on people that don’t have the means to pay for it,” Canavan told the Nine Network’s Today show.

“This so-called tax on unrealised gains is incredibly unfair. We should have a basic principle that we should only tax people where you’ve got some sort of income to be able to pay the tax man.”

But Waters said the increase would “raise revenue” for things such as hospitals, schools and clean, cheap renewable energy.

“I think it’s important to remember that nobody watching your show would be impacted by this tax,” she said.

“It would touch only half a per cent of people – we are talking about folk who have an awful lot of money in their super accounts. That is not ordinary people.

“Let’s see what the government comes up with themselves about what the details should be [and] we will have those discussions when the government puts something on the table.”

Labor wants to double the concessional tax rate on the proportion of superannuation balances above $3 million, to 30 per cent.

The policy was formulated after Treasury noticed a handful people appeared to be using the system to reduce tax, rather than solely for their retirement as intended.

One aspect of the policy, to tax unrealised capital gains on those very large accounts, has proven contentious. Many of the affected accounts are set up under self-managed super fund structures.

Unrealised gains are “paper profits” – increases in the value of assets such as properties or shares that haven’t been cashed in.

Taxing them is is already part of the Australian tax system, including under land tax regimes.

“The problem with unrealised gains is a lot of people out there, like farmers who have assets in superannuation, they may be asset rich, but they’re cash poor, and they don’t have the cash flow, to pay a tax bill on an annual basis that could come under this scheme,” Canavan said.

Treasurer Jim Chalmers has described the proposed change, which was first flagged more than two years ago and is still before the Senate, as “modest”.

“What this change is about, it’s about making concessional treatment for people with very large superannuation balances still concessional but a little bit less so,” he said last month.

“In terms of the calculation of unrealised gains, that’s actually not unique in the system.

“If you make a loss you can carry the loss forward.”

On Tuesday, Albanese said that if the Coalition was willing to negotiate a deal on the changes, then that was “good”.

“I welcome the fact that they’re saying that they won’t just say no to everything from the very beginning but we’ll, of course, talk to people in the Senate,” he said.

Albanese noted that some super accounts are worth more than $100 million.

“That’s not really to provide for an adequate retirement, is it?” he told Perth radio 6PR.

-with AAP