Third world nations were offered about 100 million Covid-19 vaccines that were near expiry, which the countries were forced to dump, according to the UN's children's fund Unicef.

According to Unicef's head of supply Etleva Kadilli, more than 100 million vaccines were, in December alone, rejected by countries as they were unable to distribute them, BBC reported.

The problem was compounded by many countries' insufficient storage facilities, Kadilli was quoted as saying to members of the European Parliament on Thursday.

Many of the world's poorest countries, most of them in Africa, have been relying on the UN-backed Covax scheme for their vaccines.

The programme faced challenges in accessing doses early last year, but the situation significantly improved towards the end of 2021 with wealthier countries releasing doses they were holding.

According to provisional tracking by UNICEF, about 910 million doses were delivered through the UN-backed initiative as of December 30. Nearly half of the doses delivered in December came from three US-backed vaccine manufacturers: Johnson & Johnson, Moderna and Pfizer.

However, many of the doses offered have been close to their expiry date, and have been rejected by the recipient nations, the BBC report said.

Some countries such as Nigeria struggled with administering the vaccines forcing them to destroy expired jabs.

Only about 10 per cent of the population on the continent has been fully vaccinated.

"More than 9.4 billion vaccine doses have now been administered globally. But 90 countries did not reach the target of vaccinating 40 per cent of their populations by the end of last year, and 36 of those countries have not yet vaccinated 10 per cent of their populations," Tedros Adhanom Ghebreyesus, chief of World Health Organization.

Ghebreyesus said that more than 85 per cent of the population of Africa -- about one billion people -- is yet to receive a single dose of vaccine.

"We cannot end the acute phase of the pandemic unless we work together to close these gaps," he warned.