Two more passengers, who returned from Dubai and Cambodia, tested positive for COVID-19 at the airport here on Wednesday, taking the total number of returnees testing for the virus so far in Tamil Nadu to four.

Confirming that the two passengers had tested positive for the virus, state Health Minister Ma Subramanian said a woman and her six-year-old daughter, who returned from China via Colombo, too, had tested positive for COVID-19 at the Madurai airport on Tuesday.

The 36-year-old woman's brother, who drove the family to Virudhunagar from the Madurai airport, would also be subjected to RT-PCR test to eliminate the chances of contracting the virus, the minister said.

"The woman and her daughter tested positive for coronavirus while another girl tested negative. From China, they had travelled to South Korea and Colombo and reached Madurai airport on Tuesday," he said. Their samples were lifted based on the country of origin and travel history, the minister told reporters here.

Both are under home isolation in Virudhunagar. Their samples, as well as those of two others who arrived at the Chennai airport would be sent to the state lab for whole genomic sequencing.

The local health officials have been told to monitor and prevent the spread of the virus.

On Tuesday, Tamil Nadu had reported 10 positive cases while the number of active cases remained at 51.

The government had intensified the screening of all passengers who arrived at the four airports in the state immediately after the sudden surge in coronavirus cases in China and other countries.

"Those coming from China, Japan, Hong Kong, Taiwan and South Korea are mandatorily screened for the virus, as per the instruction of Chief Minister M K Stalin. Passengers who arrive from other destinations are subjected to two per cent random testing," Subramanian said.

The government has already activated a mass fever screening system at the Chennai, Madurai, Tiruchirappalli and Coimbatore airports for early detection of the virus, he said.

On Tuesday, the minister, while inspecting a COVID-19 mock drill at the Rajiv Gandhi Government General Hospital, here, had said that the government is fully prepared to tackle a potential outbreak.