Billionaire Bill Gates has criticised plans to impose higher rates of tax on the super-rich – like the one suggested by Alexandria Ocasio-Cortez – as being too “extreme”.

The Democratic congresswoman for New York has said she wants to tax income over $10m at 70 per cent, arguing that it is “immoral” to allow billionaires to amass great wealth amid intense poverty.

But the Microsoft co-founder said some of the left-wing proposals were “so extreme” it would only push the wealthiest people in the US to hide more of their income from the tax authorities.

“We can be more progressive without really threatening income generation,” Mr Gates told a podcast by the tech website The Verge.

The philanthropist argued that with all the stocks and assets owned by the super-rich, deciding to reform on the ordinary income rate was “a misfocus. If you focus on that, you’re missing the picture”.

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The billionaire added: “I believe US tax rates can be more progressive. Now, you finally have some politicians who are so extreme that I’d say, “No, that’s even beyond.” You do start to create tax dodging and disincentives, and an incentive to have the income show up in other countries and things.”

Ms Ocasio-Cortez said last month: “I do think that a system that allows billionaires to exist when there are parts of Alabama where people are still getting ringworm because they don’t have access to public health is wrong.”

“I don’t think that necessarily means that all billionaires are immoral,” she added. “It’s not to say someone like Bill Gates or Warren Buffet are immoral people.”

Microsoft co-founder (AFP/Getty Images)

Mr Gates and his wife Melinda Gates have been pushing back against a new wave of criticism about whether billionaire philanthropy is a force for good.

The debate sparked into life last month at the World Economic Forum in Davos, Switzerland, where the Gates Foundation was a sponsor and Mr Gates discussed global health.

On one panel, historian Rutger Bregman berated “all these stupid philanthropy schemes” and suggested such billionaire-funded giving amounted to tax avoidance that exacerbated the problems it sought to tackle.

“It feels like I’m at a firefighters conference and no one’s allowed to speak about water,” Mr Bregman said. “Just stop talking about philanthropy and start talking about taxes.”

Ms Gates said the couple see a responsibility to support other philanthropists who want to do some good with their riches.

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“We take the converse side of that, which is we say: “What can we do personally with our wealth? What can we role model for others, and how do we get other people of great wealth to give their money away?”” she told Associated Press.

The couple’s foundation has spent nearly $7 million over the last three years building up a non-profit system to support both donors and grantees.