The world’s eight richest individuals have as much wealth as the 3.6bn people who make up the poorest half of the world, according to Oxfam.

The charity said its figures, which critics have queried, came from improved data, and the gap between rich and poor was “far greater than feared”.

Oxfam’s report coincides with the start of the World Economic Forum in Davos.

Mark Littlewood, of the Institute of Economic Affairs, said Oxfam should focus instead on ways to boost growth.

“As an ‘anti-poverty’ charity, Oxfam seems to be strangely preoccupied with the rich,” said the director-general of the free market think tank.

For those concerned with “eradicating absolute poverty completely”, the focus should be on measures that encourage economic growth, he added.

Ben Southwood, head of research at the Adam Smith Institute, said it was not the wealth of the world’s rich that mattered, but the welfare of the world’s poor, which was improving every year.

“Each year we are misled by Oxfam’s wealth statistics. The data is fine – it comes from Credit Suisse – but the interpretation is not.”

‘Elite gathering’

The annual event in Davos, a Swiss ski resort, attracts many of the world’s top political and business leaders.

Katy Wright, Oxfam’s head of global external affairs, said the report helped the charity to “challenge the political and economic elites”.

“We’re under no illusions that Davos is anything other than a talking shop for the world’s elite, but we try and use that focus,” she added.

The world’s eight richest billionaires

1. Bill Gates (US): co-founder of Microsoft (net worth $75bn)

2. Amancio Ortega (Spain): founder of Zara owner Inditex (net worth $67bn)

3. Warren Buffett (US): largest shareholder in Berkshire Hathaway (net worth $60.8bn)

4. Carlos Slim Helu (Mexico): owner of Grupo Carso (net worth $50bn)

5. Jeff Bezos (US): founder and chief executive of Amazon (net worth $45.2bn)

6. Mark Zuckerberg (US): co-founder and chief executive of Facebook (net worth $44.6bn)

7. Larry Ellison (US): co-founder and chief executive of Oracle (net worth $43.6bn)

8. Michael Bloomberg (US): owner of Bloomberg LP (net worth $40bn)