Prime Minister Prayut Chan-o-cha on Thursday urged people to download onto their smartphone a Covid-19 contact-tracing app called "Mor Chana".

However, there would be no punishments for those who do not download it, so long as they inform officials of their travel plans when crossing provincial borders.

His remark came on Thursday afternoon after an announcement made by Taweesilp Visanuyothin, the Centre for Covid-19 Situation Administration (CCSA) spokesman. He said use of the app would be mandatory in the declared maximum-control zones, a statement that was strongly opposed by some critics and sparked uproar online.

Many said that there are many Thais who still don't have a smartphone and would be unable to download the app.

The CCSA spokesman earlier told a daily press briefing on the Covid-19 situation that people would have to install the Mor Chana app onto their mobile phones and use it together with Thai Chana, an app used for checking into and out of public places.

If not, they would face a jail term of up to two years and/or a fine of up to 40,000 baht, he said.

Deputy Prime Minister and Public Health Minister Anutin Charnvirakul later on Thursday responded to growing public frustrations over the Mor Chana app rule. He said in a Facebook post he had already convinced the PM that the rule would be a burden to many people.

"The PM has agreed with my explanation and will amend the order (requiring all people to have the Mor Chana app on their smartphones) and allow the use of paper-based [Covid-19 contact-tracing] instead," said Mr Anutin.

A government spokesman said anyone who feels uncomfortable with using the Mor Chana app may instead record his or her travel history and submit his or her travel itinerary at a Covid-19 checkpoint when travelling.