Australia's rich keep getting richer, with the top 1 per cent of Australians having more than double the wealth of the entire bottom 50 per cent — or more than 12.5 million people – according to Oxfam.

Key points: Oxfam's pre-Davos 2020 analysis of inequality found Australia's billionaires grew their wealth by an average of $US460 million from 2018 to 2019

Oxfam's pre-Davos 2020 analysis of inequality found Australia's billionaires grew their wealth by an average of $US460 million from 2018 to 2019 But the number of billionaires in Australia decreased from 43 in 2018 to 36 in 2019

But the number of billionaires in Australia decreased from 43 in 2018 to 36 in 2019 Globally, the wealthiest 1 per cent of people in the world have more than double the wealth of 6.9 billion people.

Oxfam's annual list highlighting inequality has found the number of billionaires in Australia decreased from 43 in 2018 to 36 in 2019, but that the number has more than tripled over the past 10 years and the value of their wealth is still increasing.

The report, being released ahead of the 2020 World Economic Forum in Davos, Switzerland, found that the wealth of Australian billionaires, who are mostly men, grew by an average of $US460 million from 2018 to 2019.

Oxfam Australia chief executive Lyn Morgain said the top 1 per cent of Australians, just 250,000 people, owned nearly $US1.6 trillion — equating to 22.2 per cent of the nation's wealth.

"This concentration of wealth in the hands of the super-rich is occurring while the share of wealth of the bottom half of our community has decreased over the last decade and workers' wages continue to stagnate in Australia," she said.

The world's billionaires, 2,153 people in 2019, have more wealth between them than 4.6 billion people.

The report found the richest 22 men in the world own more wealth than all the women in Africa.

The World Economic Forum meets annually in Davos, Switzerland and is dominated by business and political leaders and billionaires. ( AP: Markys Schreiber )

Global inequality 'shockingly entrenched'

At a global level, inequality was "shockingly entrenched and vast, often affecting women and girls the most", Ms Morgain said.

Australia's 10 richest: 1. Gina Rinehart $15.3b 2. Harry Triguboff $9.3b 3. Anthony Pratt $7.2b 4. Scott Farquhar $7b 5. Mike Cannon-Brookes $7b 6. Frank Lowy $6.5b 7. Andrew Forrest $5.4b 8. John Gandel $4b 9. James Packer $3.6b 10. Lindsay Fox $3.5b (Source: $US, based on 'real' wealth, Forbes Billionaires List, February 2019)

"The wealthiest 1 per cent of people in the world have more than double the wealth of 6.9 billion people.

"This is not fair or sustainable."

It said the monetary value of women's unpaid care work globally, for women aged 15 and over, is at least $10.8 trillion annually — three times the size of the world's tech industry.

Oxfam's report cited World Bank figures showing almost half the world is trying to survive on $5.50 a day or less.

According to Forbes' Billionaires List, the world's wealthiest man in 2019 was Amazon founder Jeff Bezos with an estimated fortune of $US131 billion.

According to Forbes' Billionaires List, the world's wealthiest man in 2019 was Amazon founder Jeff Bezos with an estimated fortune of US$131 billion. ( AP/Patrick Semansky )

He was followed on the Forbes list by Microsoft's Bill Gates ($US96.5 billion), and US investor and CEO of Berkshire Hathaway, Warren Buffett ($US82.5 billion).

Call to collect more tax from wealthy and multinationals

Oxfam said taxing an additional 0.5 per cent of the wealth of the richest 1 per cent over the next 10 years is equal to investments needed to create 117 million jobs in education, health, elderly care and other sectors to close care deficits.

Ms Morgain said Oxfam had calculated that developing countries lose an estimated $US100 billion a year in tax revenue as a result of tax avoidance by multinational corporations.

"Given the state of inequality in Australia and abroad, and the context of worsening climate-related disasters, such as the bushfires, the Australian Government must ensure that multinational corporations are paying their fair share of tax," she said.

"This would boost public funding to allow it to provide better services to all Australians and better respond to disasters, both here and across the world."

Ms Morgain called on the Federal Government to introduce publicly available country-by-country reports on the tax affairs of multinationals and to introduce a public register of beneficial ownership of companies and trusts.

Globally, there are also calls from economists and others to introduce a global minimum tax on companies worldwide.

Oxfam's report is based on data from the Credit Suisse Global Wealth Databook, published in the second quarter of 2019, as well as the Forbes Billionaires List published in February 2019.