A number of European countries have already suspended the vaccine pending an investigation into reports of blood clots in some people.
Thailand has delayed the use of the AstraZeneca vaccine, joining a number of European countries to do so after reports of blood clots in some people.
A media event where Thai Prime Minister Prayuth Chan-ocha was to receive the AstraZeneca jab was cancelled less than an hour before the scheduled time.
Denmark, Norway and Austria are among countries which have temporarily suspended the use of the vaccine, following reports of blood clots in some people who had received it.
Health authorities have insisted the move is a "precaution", with no direct link yet between the clots and the jab.
The vaccine has been given a green light by several regulators including in the UK, EU and World Health Organization.
In place of the Thai PM’s public vaccination, health officials held an emergency news conference explaining the reasons for the delay.
Professor Yong Poovorawan, an advisor to Thailand's vaccination program, said the delay, pending the investigation in the cause of the reported side effect, will not have a great impact on the country's vaccination plan.
Thailand started its vaccination campaign last month with 200,000 doses of China's Sinovac vaccine.