Pregnant women living in areas of Thailand prone to Zika outbreaks are to be tested for the virus, the Thai Health Ministry said on Monday.

The move comes after two newborns were diagnosed last Friday with microcephaly linked to the Zika virus, the first cases in Southeast Asia.

Microcephaly is a severe birth defect where a baby's head is abnormally small. Although it can be caused by many factors, it has been linked with the Zika virus, which is spread primarily by mosquitoes.

There is currently no treatment available for microcephaly, according to Dr Tawee Chotpitayasunondh, a paediatrics specialist.

Tawee told DPA that only "supportive care" is available for babies suffering from microcephaly, adding that severity can vary in each case.

Health Ministry officials have urged the public to be vigilant of Culex mosquitoes, also known as common house mosquitoes, the main carrier of the Zika virus.

However, the ministry is also urging the public to remain calm, while downplaying the effects of the virus that was first discovered in the country since 2012.

Since January 2016, a total of 44,396 cases of insect-related diseases have led to 33 deaths, according to the Health Ministry. There have been 392 cases of Zika.