One of Asia's poorest countries, Cambodia is offering the AstraZeneca vaccine as a third shot to those who have received the inactivated virus vaccines developed by Sinopharm and Sinovac, with the aim of bolstering immunity against the COVID-19 Delta variant.

"This is for all of us to fight together and if all of us get the vaccination then we can stop the spread," said nurse Touch Phavana, 56, who was receiving a booster.

"It can prevent severe illnesses for the patients who get infected, so it is easier for us to treat them or save their lives."

Cambodia has recorded nearly 84,000 cases and more than 1,600 deaths from the coronavirus.

It has administered at least one vaccine dose to half of its population, among the highest rates in Asia, with vaccine diplomacy playing a key part in its success.

Priorities for the boosters are medical staff, government employees and frontline workers.

The country has benefited from its relatively small population of just over 16 million and a low-income status making it eligible for the COVAX vaccine-sharing initiative.

"I hope that when we finish this third dose of vaccines, then firstly we can reopen the schools for our children to study in class again, so we get our workforce back," said bank worker Try Sokhim, 26.

"Second, we can get our tourism industry up again."

Cambodia has administered at least one coronavirus vaccine dose to half of its population, among the highest rates in Asia, official data showed on Wednesday, with vaccine diplomacy playing a key part in its success.

Cambodia, an ally of China and one of Asia's poorest countries, started inoculations with Chinese-made vaccines in February, while millions of doses provided by the United States, Japan and Britain have arrived in recent weeks.

Prime Minister Hun Sen on Tuesday said Cambodia should reach the 10 million people targeted for vaccination about seven or eight months earlier than planned.

Of Cambodia's more than 16 million people, 8.3 million have received at least one dose, while 6.4 million of those have received both required shots.

The rate is similar to Malaysia's 49.4 percent receiving a first dose, but higher than the 25 percent of the population in neighboring Thailand and 12 percent of people in Vietnam.

China has provided 18.7 million doses to Cambodia, of which 3.2 million were donations, according to the Chinese embassy.

The US announced this week it would provide Cambodia with an additional $4 million in urgent assistance after donating one million doses of Johnson & Johnson's vaccine through the COVAX vaccine-share initiative.

"The United States will continue to donate additional vaccine doses globally in the coming months as supply becomes available," said Chad Roedemeier, a US embassy spokesperson.