MANILA - At least 49 resorts and restaurants in the tourist island of Siargao were found operating without sewage treatment facilities and did not have environmental compliance certificates, the Department of Environment and Natural Resources said Tuesday.

The business owners will be served notices of violation and ordered to "address environmental problems" in the popular surfing destination, according to the DENR.

Authorities are cracking down on violators of environment laws after pollution turned portions of Boracay into a "cesspool," according to President Rodrigo Duterte. It may be temporarily closed to tourists this year.

• Duterte slams Boracay as ‘cesspool,’ threatens to shut down island

"Siargao is still one of the country’s best tourist destinations, but if we want to sustain its viability as an international surfing capital, we must show that we are all helping to protect and conserve its environment,” Environment Secretary Roy Cimatu said in a statement.

The serving of notice of violations is expected to be completed by the end of March, Cimatu said.

From there, the DENR will determine "whether to elevate the case to the Pollution Adjudication Board,” Cimatu added.

The government started inspecting the environment compliance of businesses operating in popular tourist destinations last month, after President Rodrigo Duterte threatened to shut down Boracay island if its "cesspools" would not be cleaned up in 6 months.

Aside from Boracay and Siargao, the government has also inspected beach front businesses in Bohol's Panglao Island and Ilocos Norte's Pagudpud.