Australia says it is sending 10,000 Covid-19 vaccine doses to Fiji this week, and double that amount to Timor-Leste.
Fiji has reportedly run out of vaccine doses, at a time when its health authorities are scrambling to contain community transmission of the coronavirus.
The country has already used 50,000 AstraZeneca doses for its national vaccination programme.
Another 10,000 doses will be delivered by Australia to its partners in Fiji this week via the Covax facility, according to a joint statement from Greg Hunt, Australian Minister for Health and Aged Care and Zed Seselja, Minister for International Development and the Pacific.
"Australia will procure vaccine stocks, under a partnership agreement with UNICEF, of up to 6 million Covid-19 doses for the Pacific and Timor-Leste in 2021.
"This commitment is in addition to Australia's $80 million (US$61 million) contribution to the multilateral COVAX Facility's Advance Market Commitment for developing countries.
"More than 275,000 COVID-19 vaccine doses have already been delivered by COVAX to Timor-Leste, Papua New Guinea, Solomon Islands, Fiji, Tonga, Samoa, Tuvalu and Nauru."
Australia is also providing 20,000 Covid-19 vaccine doses from its national stocks to Timor-Leste.
It is also sending medical supplies to support Timor-Leste's response to its Covid-19 outbreak which worsened after devastating floods last month.
Australia's government says this builds on more than 56 tonnes of humanitarian, medical and PPE supplies delivered to Timor-Leste last month.
Six Australian Medical Assistance Team specialists are currently in Dili working to support local health authorities in their Covid response.