"These sporadic, small-scale, charitable handouts from rich countries to poor countries is not a serious plan and it will not bring the pandemic to an end," Lowcock, who steps down on Friday, told Reuters on Monday.

"The G7, essentially, completely failed to show the necessary urgency."

The leaders of the United States, Japan, Germany, Britain, France, Italy and Canada met in Cornwall, England at the weekend and also agreed to work with the private sector, the Group of 20 industrialised nations and other countries to increase the vaccine contribution over months to come.

"They took a small step - at that very, very nice resort in Cornwall - but they shouldn't kid themselves it's more than a small step and they have still have a lot to do," Lowcock said.

"What the world needed from the G7 was a plan to vaccinate the world. And what we got was a plan to vaccinate about 10 per cent of the population of low and middle income countries, maybe by a year from now or the second half of next year," he said.

In May, the International Monetary Fund unveiled a $US50 billion proposal to end the COVID-19 pandemic by vaccinating at least 40 per cent of the population in all countries by the end of 2021 and at least 60 per cent by the first half of 2022.

"That is the deal of the century," said Lowcock, adding that the G7 could also have done a lot more to provide vital supplies - such as oxygen ventilators, testing kits and protective equipment - to countries who are going to have to wait longer for vaccines.

UN Secretary-General Antonio Guterres on Friday urged world leaders to act with more urgency, warning that if developing countries were not vaccinated quickly, the virus would continue to mutate and could become immune to inoculation.

Australian Associated Press