The world is on the "brink of a catastrophic moral failure" if rich countries hog Covid-19 vaccine doses while the poorest suffer, the head of the WHO said Monday.

World Health Organization director-general Tedros Adhanom Ghebreyesus denounced the "me-first" attitude of wealthy nations and also blasted vaccine manufacturers for chasing regulatory approval in rich countries rather than submitting their data to the WHO to green-light vaccine use globally.

He said the promise of worldwide equitable access to vaccines against the coronavirus pandemic was now at serious risk, in a speech in Geneva opening a WHO executive board meeting.

Tedros said 39 million doses of the coronavirus vaccine had been administered so far in at least 49 higher income countries.

Meanwhile, "just 25 doses have been given in one lowest income country. Not 25 million; not 25,000; just 25," he said.

"I need to be blunt. The world is on the brink of a catastrophic moral failure -- and the price of this failure will be paid with lives and livelihoods in the world's poorest countries."

He said even as some countries pronounced reassuring words on equitable access, they were prioritising their own deals with manufacturers, driving up prices and trying to jump the queue.

He said 44 such deals were struck in 2020 and at least 12 have already been signed since the New Year.

"The situation is compounded by the fact that most manufacturers have prioritised regulatory approval in rich countries where the profits are highest, rather than submitting full dossiers to WHO," Tedros said.

"Not only does this me-first approach leave the world's poorest and most vulnerable people at risk, it's also self defeating.

"Ultimately, these actions will only prolong the pandemic, prolong our pain, the restrictions needed to contain it, and human and economic suffering."