The emergency decree looks set to continue for another month as security authorities are still "not confident" about the Covid-19 situation following the easing of the lockdown since early this month, a military source says.

Their stance was revealed as Prime Minister Prayut Chan-o-cha on Wednesday met military top brass to address the Covid-19 outbreak that was "wreaking havoc on people from all walks of life", the source said.

The source said military chiefs are ready to follow the government's wishes if it decides to extend the decree. Staunch enforcement will continue until the pandemic eases off, the source said.

The National Security Council, the National Intelligence Agency and military agencies have been keeping a close watch on the easing of business shutdowns since May 17, a day which saw large numbers of people flocking to shopping malls.

According to the source, security agencies are worried over the impact on public health if the state of emergency does not continue when the Centre for Covid-19 Situation Administration (CCSA) allows more businesses and activities to reopen in June.

In this "phase 2 easing period", the government needs to wait for at least 14 days to assess whether new lockdown easing will lead to further Covid-19 outbreaks.

National Security Council secretary-general Somsak Roongsita said he will call a meeting today on the executive decree, which is due to end on May 31, between security officers and representatives from health and business sectors.

Whether to further enforce the law will depend largely on the "actual Covid-19 situation", he said. The mostly one-digit infection rates a day which are being reported at the moment are the result of strict measures under the decree last month, he said.