Military Police officers wearing protective masks are seen at a checkpoint, after a curfew was imposed to prevent the spread of the coronavirus disease in Bangkok on April 3, 2020. (Reuters photo)

Prime Minister Prayut Chan-o-cha on Friday slammed more than 6,500 curfew violators for lacking a social conscience but insisted he will not impose any tougher restrictions as current measures in dealing with Covid-19 over the past 100 days are proving effective.

Gen Prayut insisted that the government will not extend the current curfew hours beyond 10pm-4am yet or impose any additional drastic measures that restrict people's rights as public cooperation has seen infection rates fall.

"Since Jan 4, we have been fighting together against Covid-19 for almost 100 days with preparation, strict monitoring, a strong public health system and cooperation from all sides.

"We now have the number of infected patients at a controllable level, and a low death rate compared to other leading countries," said Gen Prayut who is also in charge of the Centre for Covid-19 Situation Administration (CCSA).

This is proof that the country's operations are effective and several countries have held Thailand up as a successful example of dealing with Covid-19, the prime minister said in a TV Pool broadcast on Friday evening.

However, the prime minister was dissatisfied with the large number of people who have defied curfew restrictions which rose to more than 6,500 since the curfew started on April 3, and has led many people to call for tougher measures or a longer period of curfew.

"People who lack conscience and responsibility will make life miserable for those who are struggling to earn their living. I want to warn them to correct themselves, though the CCSA still has no plan to extend the current curfew hours," he said.

Gen Prayut also emphasised that the Songkran festival has been postponed, and the public must not take part in any kind of informal celebrations or return to their home provinces during the period. He also urged people to forgo the Rot Nam Dam Hua water-pouring ceremony, a traditional rite for young people to show respect to elders and ask for their blessings.

Gen Prayut did, however, say that he had signed an order to allow people in some groups or sectors to work during the night curfew.

The order includes authorities and their assistants, including civil servants, on duty under the order of state agencies.

Patients in need of medical attention, their care-takers and all health personnel are also allowed to travel during the curfew, according to the order issued on Friday

The transport of medical supplies, consumer products, newspapers and goods for import and export is also allowed.

Those who need to be quarantined are also allowed to travel as are staff at petrol stations and public utilities.

Food delivery and refuse collection workers are exempted during the curfew hours, as well as people who need to work at night such as security guards, fishermen, rubber tappers and nightshift staff.

Meanwhile, a total of 33 Thais stranded overseas returned to Thailand on Friday, according to spokesman Taweesilp Visanuyothin at the CCSA's daily press conference.

Of them, 15 from the Netherlands arrived at Suvarnabhumi airport and will be quarantined at a hotel near the airport for 14 days.

The other 18 arrived back from Singapore and will be placed under quarantine at a hotel on Rama IX Road in Bangkok.

Dr Taweesilp also said that a total of 21 Thais stranded in Moscow, Russia will fly home on Saturday and will be quarantined at a hotel in Bangkok.

A group of 152 Thai students studying in the US on a scholarship from the American Field Service will also fly to Thailand at a date yet to be confirmed, and be quarantined at a Bangkok hotel, Dr Taweesilp said.

Chutintorn Gongsakdi, the Thai ambassador to India, said that the embassy in New Delhi has prepared for the first batch of 200 Thais who have registered to return home.

More than 1,600 Thais in India have signed up to return so far, he said, adding that upon arrival they will be quarantined for 14 days.

Mr Chutintorn said that the embassy is ready to charter flights to bring them home between April 15-17 when the Indian government allows aircraft from other countries to enter the country on April 14.

Currently, more than 20,000 Thais stranded overseas have registered with Thai embassies in foreign countries to return home.

The Civil Aviation Authority of Thailand has banned inbound flights until April 18 due to the risk of returnees being infected with Covid-19.