The announcement comes as other countries in the region like the Philippines prepare to sign similar deals with AstraZeneca and other firms to guarantee supplies.

"Tomorrow, we will sign a further agreement on the purchase of vaccines," Prime Minister Prayuth Chan-ocha said in a statement, adding that he expects it to be verified and ready for use by the middle of next year.

"The Oxford University-AstraZeneca team announced that the vaccine they are developing has been found to have between 70% to 90% efficacy," Prayuth said.

The temperature storage conditions of the vaccine of between 2-8 degrees Celsius (11.6-46.4 degrees Farenheit) also made it suitable for the country, he said.

Thailand's cabinet previously approved a budget of 6 billion baht ($198 million) for the purchase for 26 million doses for the immunisation of 13 million people.

Southeast Asia's second-largest economy has kept total coronavirus cases at a low 3,942, with 60 deaths, but its ban on commercial flights imposed in April has battered its important tourism industry and slowed recovery efforts.

The vast majority of new coronavirus cases in Thailand in recent months have been imported and found in state quarantine.

(Writing by Chayut Setboonsarng; Editing by Martin Petty)

By Panarat Thepgumpanat