MANILA—The Philippine health department "may be underreporting" the number of novel coronavirus (COVID-19) cases, Sen. Panfilo "Ping" Lacson said Saturday, hours after Health Secretary Francisco Duque III confirmed the 6th case of the disease raised Code Red alert status in the country.

• CODE RED: Philippines' coronavirus cases rise to 6, DOH confirms local transmission

"Do we have enough testers to cover a decent number of our population, especially in the more vulnerable areas of the country? If no, the DOH may be underreporting, albeit unintentionally," Lacson said in a statement.

The senator stressed that responding against the dreaded disease "is a top health priority, and government must invest heavily not only on prevention and cure by way of research, but also on containment."

"We have many homegrown medical experts in and out of government," he said. "This is one phenomenon that should bring us together as a nation."

The Department of Health (DOH) on Friday confirmed the Philippines' 4th and 5th COVID-19 cases -- including its first-ever local transmission -- more than a month after it announced the third coronavirus patient in the Southeast Asian country.

• Philippines' new coronavirus cases now at 5, including potential local transmission

The department announced the development after Taiwan's health ministry said that one of their citizens who recently traveled to the Philippines tested positive for COVID-19.

• Taiwanese with PH travel history tests positive for COVID-19

Due to the number of virus cases in the Philippines, the DOH placed the country's alert status on the disease to Code Red Sub-level 1, requiring all health personnel to report for duty in their respective facilities to provide medical services.