The Greens leader, Richard Di Natale, will use a speech to the National Press Club on Wednesday to “kick off a conversation” about Australians working less, flagging a four-day week or a six-hour day as automation drives job shedding across the Australian economy.

Di Natale will also telegraph a new housing affordability policy, to be released by the Greens shortly, which will include reform of negative gearing and capital gains and “a transition plan for the states” to abolish stamp duty.

In a wide-ranging speech that will take in reform of political donations, options to improve housing affordability, the desirability of wealth taxes, including a “Buffett” rule, a “people’s bank” to improve retail competition and ending tax breaks for private health insurance, Di Natale will argue the case for guaranteed adequate income to deal with emerging pressures in the economy.

Di Natale will warn that automation and digital disruption will means the loss of 5m jobs in the Australian economy over the coming decade and it’s time for politics to start grappling seriously with the consequences.

“We want to kick off a conversation about the future of work and start by questioning the entrenched political consensus that a good life can only come from more work,” the Greens leader will tell the press club.

“It’s a discussion that must include the things we really value in life, like relationships and being with our loved ones, leisure, sport, volunteering, creativity and all the simple things that make us happy.

“We rightly talk about the 16% of people who want to work more hours but we never hear about the more than one in four Australians who want to work less.

“A four-day work week, or a six-hour day might actually make us happier and create more opportunities for others, not to mention reducing the costs of full-time childcare. Some companies have even implemented three-day working weeks.”

Di Natale believes the discussion can’t happen without reference to guaranteed adequate income, which is a policy the Greens have been flagging for some time. “Many other countries are trialling models of a social security safety net that are designed to look after everyone in a 21st century economy where work has changed radically,” Di Natale will say.

The Greens leader will also point to the imminent release of a new housing affordability policy as the Turnbull government continues to float various policy options in the lead-up to the May budget.

Di Natale will say the new Greens policy will include a plan to get rid of stamp duty. “Stamp duty raises the price of housing and stops people from moving between homes even when they want to so it’s about time we levelled the playing field and got rid of it.”

Victoria announced recently it would abolish stamp duty for first home buyers purchasing a property valued below $600,000 as part of a housing affordability strategy.

The federal treasurer, Scott Morrison, said abolishing stamp duty would not reduce home prices unless more housing supply was brought onto the market.

The government has been floating options it could include in the May budget to boost housing affordability. On Tuesday, Michael Sukkar, the assistant minister to the treasurer, suggested the government may allow first home buyers to use their superannuation to buy a home if the policy were “finely calibrated”.

The Greens leader will argue “a people’s bank, one that injects real competition into the banking system” would be able to pursue social objectives “like housing affordability, not just profit-driven ones”.

Di Natale will restate the Green’s support for a Buffett rule – and note positively the emerging debate within Labor ranks about a minimum rate of tax for high income earners.

Some Labor left figures support a debate about a Buffett rule and, for the first time last month, one of the party’s senior right wingers, former treasurer Wayne Swan, threw his support behind the measure.

Bill Shorten and the shadow treasurer, Chris Bowen, aren’t fans of the concept. “We think that for sheer efficiency ... at this point reforming negative gearing is one of the best redistributive mechanisms we can do,” Shorten told a meeting in Canberra just over a week ago.

This week’s Guardian Essential Poll found a clear majority of voters supported a range of tax increases, including a Buffett rule.