LONDON - A report by Oxfam suggests Bill Gates could become the world's first trillionaire - but critics have poured cold water on the claim.

According to the recent report by Oxfam - a leading British charity fighting global poverty - eight billionaires from around the globe have as much money as the 3.6 billion people who make up the poorest half of the world's population.

The report also finds that, given the exponential growth of existing wealth, the world could have its first trillionaire in the next 25 years, when Gates would be 86.

The 61-year-old Microsoft founder, who was the world's youngest billionaire in 1987 at the age of 31, could be worth US$1,000,000,000,000 by the year 2042, the report says.

It is a claim that one critic describes as "ludicrous".

When Gates left Microsoft in 2006, his net worth was US$50 billion, according to Oxfam. By 2016, his wealth had increased to US$75 billion, "despite his commendable attempts to give it away through his Foundation," the report says.

In addition to the charitable work Gates does through his personal foundation, he is one of the founding members of The Giving Pledge, a commitment from some of the richest individuals in the world to give away more than half of their worth, said CNBC.

For the hypothetical analysis, Oxfam researchers applied the average rate of growth the ultra-rich have been enjoying, 11 per cent per year since 2009, to Gates' current levels of wealth (over US$84 billion, according to Forbes).

If his investments keep doing as well as they have been, 61-year-old Gates could indeed become the world's first trillionaire.

"In such an environment, if you are already rich, you have to try hard not to keep getting a lot richer," Oxfam notes.

However, economics expert Tim Wortsall, a Forbes contributor, argues that Oxfam's claims are "ludicrous'".

Looking at the numbers, Wortsall explains: "In the proper jargon, they are confusing a cycle in the economy with a structural feature of the economy.

"Bill Gates to be world's first trillionaire soon? Most likely, in fact almost certainly, the answer here is 'No'," he concludes.

He suggests Gates will actually be worth nearer to US$133 billion by 2042.

Nevertheless, Oxfam GB chief executive Mark Goldring says in the rport: "This year's snapshot of inequality is clearer, more accurate and more shocking than ever before. It is beyond grotesque that a group of men who could easily fit in a single golf buggy own more than the poorest half of humanity.

"While one in nine people on the planet will go to bed hungry tonight, a small handful of billionaires have so much wealth they would need several lifetimes to spend it.

"The fact that a super-rich elite are able to prosper at the expense of the rest of us at home and overseas shows how warped our economy has become."