LONDON - It is not right for the Bill & Melinda Gates Foundation to play such a big role in global health funding, but the group will not back away until others step up, its chief executive said.

The Gates Foundation has faced criticism that it has too much power and influence in the global health realm, including within the World Health Organization, without the requisite accountability.

In his annual letter released on Tuesday, chief executive Mark Suzman hit back at the criticism as he revealed that the foundation would spend $8.3 billion this year, its highest ever annual budget.

"It's not right for a private philanthropy to be one of the largest funders of multinational global health efforts," he said, adding that countries ought to be leading the charge.

"But make no mistake- where there's a solution that can improve livelihoods and save lives, we'll advocate persistently for it. We won't stop using our influence, along with our monetary commitments, to find solutions."

Suzman said the aim of the fund was not to set the agenda for the WHO or other global health groups, but to provide them with better options and data as they make key decisions.

Bill and Melinda Gates, the tech billionaires-turned-philanthropists who set up the foundation, have long defended their efforts amid questions over whether their vast payouts give them undue influence and impact in global development.

Alongside funding efforts to eradicate diseases like malaria and polio, the Gates Foundation is also the second biggest donor to the WHO, one of the issues that critics have regularly raised about its role, particularly during the COVID-19 pandemic.

"I'd love it if many more governments would pass us on that list - because that would mean more lives saved," wrote Suzman.

Last year, the WHO agreed a deal that would see member states increase their guaranteed contributions, reducing the role of private donors and allowing the United Nations agency more flexibility on spending.

(Reporting by Jennifer Rigby Editing by Mark Heinrich)