The government wants to buy another 35 million Covid-19 vaccine doses, taking its total order to 63 million, Prime Minister Prayut Chan-o-cha said on Monday.

Prayut did not say where the extra doses would come from but stressed the government needed to be sure they were safe, had no side effects and were in line with standards set by the country's Food and Drug Administration (FDA).

The first order of 2 million doses will arrive from China in the next three months, with the government prioritising who should get them, Prayut said.

It also recently signed a deal with AstraZeneca for 26 million doses and the right to produce its Covid-19 vaccine in Thailand, with supplies expected by May. That vaccine will be produced by Thailand's Siam Bioscience with a formula and technology developed by AstraZeneca and the University of Oxford.

The Public Health Ministry says the first batch will come from Chinese company Sinovac Biotech, with 200,000 doses due to arrive by the end of next month.

The second batch of 800,000 doses will be shipped to Thailand by the end of March, and the last batch of one million doses will arrive by the end of April.

Healthcare personnel and village health volunteers will be offered the first doses.

Prayut also said his government was assessing the situation daily.

"We don't want to lock down the entire country because we know what the problems are, so can you all lock down yourselves?" he said.

"This is up to everyone, if you don't want to get infected just stay home for 14 to 15 days. If you think like this then things will be safe, easier for screening."