Myanmar has been in turmoil since the military ousted civilian leader Aung San Suu Kyi, and the latest wave of the pandemic has struck with many hospitals empty of pro-democracy medical staff.
The shipment contained 736,000 Sinopharm doses, according to media controlled by the State Administration Council -- as the junta dubs itself.
The junta has purchased four million vaccines from China, it said earlier this month, adding Beijing will donate a further 2 million.
But widespread anger at the coup -- and fear of being seen to cooperate with the regime -- is keeping many away from military-run hospitals.
Instead, volunteer groups across the country are fighting desperate battles to source precious oxygen and bring the dead for cremation.
On Thursday, a shadow government of ousted lawmakers said it had formed its own Covid taskforce, and would seek international support to procure vaccines.
The "National Unity Government", whose members are in exile or underground, did not make clear how it would be able to secure and administer vaccine doses in Myanmar.
Around 1.75 million people have so far been vaccinated in the country of 54 million, according to authorities.
Beijing enjoys exceptional leverage over Myanmar and has refused to label the military action a coup.
Myanmar on Wednesday reported 6,701 new cases -- up from around 100 per day in early June.
Earlier this month, state media reported junta leader Min Aung Hlaing had agreed to buy two million vaccines from Russia -- another major ally -- without specifying which shot.
Myanmar's creaking healthcare system had struggled to respond to Covid even before the generals' putsch.
Swathes of the country were put under partial lockdown last year, although enforcement was often lax in the developing nation where many face a stark choice between following regulations and feeding their families. - AFP