The government is expected to reach a deal soon with British drugmaker AstraZeneca PLC to secure over 100 million doses of a novel coronavirus vaccine being developed with the University of Oxford, a source close to the matter said Friday.

The drugmaker has announced that it will start supplying its COVID-19 vaccine overseas in September, and is expected to begin clinical trials in Japan later this month to confirm its efficacy and safety.

Japan has already reached an agreement to receive a supply of 120 million doses of a novel coronavirus vaccine for 60 million people by the end of June next year from U.S. pharmaceutical giant Pfizer Inc. and its German partner BioNTech SE., if they succeed in its development.

AstraZeneca, which has been conducting a final-stage clinical trial of its experimental AZD1222 vaccine overseas, has not yet decided whether to recommend one or two doses of the vaccine per person once it is put into practical use.

The British company is in talks with JCR Pharmaceuticals Co. in Hyogo Prefecture to produce vaccine solutions, and with Tokyo-based Daiichi Sankyo Co. for packing and storing of the vaccines.

The drugmaker's COVID-19 vaccine is among the world's most advanced vaccine candidates. The company has said the vaccine showed robust immune responses in all participants in early-stage trials.