The United States called Tuesday for more transparency around the WHO's finances before any sweeping funding reforms requested to strengthen the agency leading the global battle against Covid.

The World Health Organization and a large number of member states have been rallying for a significant financing overhaul, arguing it needs more reliable and flexible funds to meet the swelling challenges at hand.

While agreeing there is a need to ensure more sustainable financing for the UN health agency, the United States -- one of the WHO's top donors -- said Tuesday it first wanted to see governance reforms and increased transparency around its finances.

"The US seeks to better understand the current funding mechanisms, efficiencies and decision-making before considering an increase in assessed contributions," Loyce Pace, assistant secretary for global affairs at the US health department, told a WHO executive board  meeting.

Assessed contributions, or membership fees, paid by the WHO's 194 member states, calculated according to wealth and population, have in recent decades covered a dwindling share of the budget.

Back in the 1980s, they accounted for around 80 percent of the WHO budget. Today they cover just 16 percent.

'Unsustainable'

That has left the agency responsible for coordinating the global response to the pandemic, and a slew of other health emergencies, increasingly at the mercy of voluntary contributions from countries and other donors.

Such contributions tend to be tied to specific programmes, emergencies and crises, and are far less reliable and offer less flexibility to respond when and where needs arise.

"The current model for financing the WHO is unsustainable," the agency's chief Tedros Adhanom Ghebreyesus told the executive board.

"A phased increase in assessed contributions would be a game-changer, and help to make us (the) strong organisation you want us to be."

Tedros, who on Tuesday was nominated to serve a second five-year term, has been leading the call to gradually increase the share of the WHO's budget -- which for 2020-2021 stood at nearly $6 billion -- covered by assessed contributions.

Experts have said such contributions should account for at least 50 percent of the budget by 2028-2029.

But there has been no consensus among countries to put the proposal to vote at the WHO's next decision-making assembly in May.

A range of countries spoke up during the board meeting to call for such an increase, while some suggested assessed contributions should make up a larger share, and others voiced concern at the financial burden a hike would impose on poorer countries. 

Tedros meanwhile stressed his support Tuesday for governance reform and improving transparency, but said it could happen in parallel with reform of WHO financing. 

"If it's taken as a precondition, we will move in a vicious circle," he said.

"If we do it side by side, then we can move from the vicious circle to a virtuous circle."

Austrian representative Clemens Marin Auer meanwhile highlighted that strengthening WHO financing was about ensuring its "independence".

"It is a question of the existence of the organisation."