Richard Di Natale makes the case for a nationalised bank – “the People’s Bank” – to address lacklustre competition in Australia’s banking industry, in his address to the National Press Club on Wednesday.

The Greens leader argues the banking royal commission, and the housing affordability crisis all point to a system – aided and abetted by successive governments – that has failed Australians. He maintains the only way to get things back on an even playing field is government intervention in the form of a bank backed by the Reserve Bank of Australia and focused “on the everyday savings and mortgage needs of customers”.

“By offering a no-frills ‘mortgage tracker’ account to homeowners, people paying off their home will be able to borrow up to 60% of the value of the property directly from the RBA,” according to Di Natale’s speech notes.

“The minimum interest rate would be set at 3%, plus approximately 0.5% for the administration costs of contracted service providers. The interest rate would go up with the cash rate, if it rises above 3%, but it will always deliver loans that householders can pay off faster, and with significant savings on interest, compared to the current offerings of the big banks.”

Just how significant those savings would be depends on the size and the life of the loan. But the Greens estimate a $600,000 home, with a $90,000 deposit, would mean $360,000 borrowed from the People’s Bank, with the shortfall of $150,000 borrowed from a retail bank.

That combined loan, the Greens predict, could be paid off in 21 years and eight months, with $227,311 paid in interest, three years and four months sooner and $113,102 cheaper than a traditional, retail only, loan.

To even the playing field, the mortgage-tracker accounts would only be available to people with “no other direct residential property holdings, including through self-managed superannuation funds and private trusts”.

“This is so as to prevent people gaming the system by using the People’s Bank to cross-collateralise investment properties,” Greens policy documents state.

“It’s already easy enough for baby boomers to buy their fifth rental property. The role of the People’s Bank isn’t to make it easier still.”

The Greens are not alone with the proposal for a nationalised bank – both One Nation and Katter’s Australian party have previously floated the idea of a government-owned bank as the answer to farm and landowners’ woes.

Having embraced the ACTU call for an end to inequality, which included pathways for casual workers to become permanent, and more job security, Di Natale has also committed the Greens to a universal basic income.

“We need a universal basic income that ensures everyone has access to an adequate level of income, as well as access to universal social services, health, education and housing,” Di Natale’s speech says.

“A UBI is a bold move towards equality. It epitomises a government which looks after its citizens, in contrast to the old parties, who say ‘look out for yourselves’. It’s about an increased role for government in our rapidly changing world.”

Part of that increased role for government also includes renationalising part of the electricity market, including the interconnectors between states and a government-owned energy retailer.

“The Greens are the only party proudly arguing for a much stronger role for government,” Di Natale will say.

“Today’s problems require government to be more active, and more interventionist, not less.”

After losing the chance to take Batman – described as Australia’s most progressive seat – Di Natale acknowledges that “heading into an election with Labor in opposition, it can make the progressive space suddenly appear a little more crowded”.

“Labor will continue to veer wherever the electoral wind blows, as we’ve seen with their ongoing internal struggles over issues like the Adani coalmine and their refugee policy,” Di Natale says in his speech.

“Ultimately what sets the Greens, and our progressive agenda apart, is that no other party has fully accepted the central challenge facing our species, that without a healthy environment, there is no economy.”

Di Natale will speak just after lunchtime on Wednesday.