Public Health Minister Anutin Charnvirakul on Tuesday defended the government over criticism it was taking too long to start vaccinating Thais against the coronavirus.

Thanathorn Juangroongruangkit, leader of the Progressive Movement, said the government was moving too slowly and had only reserved enough vaccines for 21.5% of population in the short term.

Even by 2023, he said, it was only on course to vaccinate just 50% of the population, far short of the 70% minimum to create herd immunity.

Mr Anutin, however, said the government had arranged to vaccinate 70% of Thais by the end of 2022, not a whole year later, as Mr Thanathorn claimed.

"Our Covid-19 vaccine programme is not slow. We are just following our plan," Mr Anutin said.

"Furthermore, we also have the capability to produce Covid-19 vaccines locally so we don't have to worry about competing over vaccines with other countries," he added.

The first vaccination phase is due between February and April, using 150,000 doses of the AstraZeneca vaccine shipped from Italy.

The first person is scheduled to be vaccinated in the middle of February -- it is tentatively set for Valentine's Day, Feb 14 -- and the government's plan is to use the first 50,000 doses to inoculate the elderly and 7,000 medical staff in Samut Sakhon.

The government then plans to use two million doses from Sinovac, the Beijing-based biopharmaceutical company.

The second phase, from May to December, will see doctors using about 26 million doses of the Oxford/AstraZeneca vaccine, produced locally by Siam Bioscience.

The third phase, starting in January next year, will see 35 million doses of the AstraZeneca vaccine.