Walk-in services for Covid-19 vaccination will not be ready until next month, authorities said on Thursday.

The message disappointed many people after the government announced on Wednesday that its walk-in services would be available in any province that was ready to give free jabs to those who wanted them.

Many people on Thursday contacted hospitals to book their shots and some even walked into vaccination sites requesting them but they were disappointed as authorities said there were no vaccines available on a walk-in basis.

"I told the BMA and the ministry to clarify to prevent any misunderstandings. The services will be ready by June," said Prime Minister Prayut Chan-o-cha.

He said he had told the Public Health Ministry and the Bangkok Metropolitan Administration (BMA) to make things clear.

"I confirm the government plans [to offer] walk-in services if there are enough vaccine doses," Prayut said.

"Rest assured, everyone will receive the vaccine shots for sure."

The prime minister insisted that the AstraZeneca vaccine would arrive in Thailand next month as planned.

The country has also stockpiled the Sinovac vaccines from China, he said.

"We will see mass vaccinations starting by next month when we have many millions of doses on our hands," said the Health Minister.