HSBC and the Asian Development Bank (ADB) will provide a combined financing of $300 million to help Asia's supply chains boost manufacturing capacity for COVID-19 vaccines, the two lenders said on Friday.

The initiative builds on a risk-sharing scheme the banks launched in July to help to fund suppliers of personal protective equipment (PPE) as they and vaccine makers race to meet the huge global demand that outstrips supply.

By leaning on the ADB's sovereign-level credit rating, private sector lenders such as HSBC can lend more easily to companies in the complex chain of vaccine supply production, HSBC said.

"Right now demand for vaccines far outstrips supply and one of the challenges is that supply and distribution networks have to be formed, which requires a lot of liquidity," said Surath Sengupta, global head of financial institutions at HSBC.

The lenders will offer funds through trade loans and invoice financing among other tools, Sengupta said, as countries across Asia try to shorten the usual multi-year time scale needed to deploy large-scale inoculation programs.

Vaccination levels in Asian countries have varied widely as governments deal with limited supplies, rapidly rising demand and political jockeying to secure doses.

Leaders of the United States, India, Australia and Japan agreed to pool financing, manufacturing and distribution capacity to send 1 billion COVID-19 vaccines across Asia by the end of 2022, India's foreign secretary said in March.