WASHINGTON (AFP) - India will manufacture at least one billion more Covid-19 vaccine doses by the end of next year in a joint initiative announced on Friday (March 12) with the United States, Japan and Australia.

Following the nations' first four-way summit, President Joe Biden's national security adviser, Jake Sullivan, said the so-called Quad had made a "massive joint commitment" to vaccines.

"The Quad committed to delivering up to one billion doses to Asean, the Indo-Pacific and beyond by the end of 2022," Sullivan told reporters.

The White House in a statement said that Indian company Biological E would produce "at least" one billion doses by the end of next year, focusing on the one-dose, US-developed Johnson & Johnson jab.

The manufacturing will be backed financially by Japan as well as the US International Development Finance Cooperation, which provides funding for projects in developing countries.

Australia will contribute another US$77 million (S$100 million), in addition to an earlier commitment of US$407 million, to ensure vaccines are not only delivered but administered in South-east Asia, the White House said.

Japan in turn will provide US$41 million for the distribution of vaccines, which requires careful climate control.

Indian Prime Minister Narendra Modi said the initiative showed unity on Covid-19.

"India's formidable vaccine production capacity will be expanded with support from Japan, US and Australia to assist countries in the Indo-Pacific region," Modi wrote on Twitter.

"Our discussions today on vaccines, climate change, and emerging technologies make Quad a positive force for global good and for peace, stability and prosperity in the Indo-Pacific."