Environmental activists are being killed in record numbers around the world, with the corruption-plagued Philippines one of the most dangerous countries, according to watchdog Global Witness.

At least 200 community activists, NGO workers and other civilians on the frontlines of protecting the environment were reported murdered worldwide last year, the highest on record, the group said.

In the Philippines, an environmental activist was recorded to have been killed at a rate of every 12 days in 2016, with only Brazil and Colombia having more murders.

As in other hotspot nations, the deaths in the Philippines are rising as communities stand up against corrupt politicians and businessmen intent on securing increasingly scarce natural resources.

"Voracious industries such as mining, agribusiness and logging are trampling over people's rights to take part in decisions that affect their land and environment," Billy Kyte, Global Witness environmental and land defenders campaign leader, told AFP.

"Forced into activism, many of these marginalised communities then receive threats and attacks for defending their rights. The government does little to stop the ensuing violence and rarely holds anyone to account for the killings."

Twelve PNNI para-enforcers have been murdered since 2001, most recently in September when 49-year-old Ruben Arzaga was shot in the head while approaching an illegal logging site KARL MALAKUNAS, AFP

Philippine President Rodrigo Duterte's controversial crackdown on drugs, which has seen police and suspected vigilantes kill thousands of people, further highlights the culture of impunity, according to rights groups.

Father-of-five Ruben Arzaga was one of the most recent land defenders murdered in the Philippines when he was shot in the head in September as he tried to approach illegal loggers on Palawan island, a popular tourist destination.

Arzaga was an elected village captain in Palawan's tourist town of El Nido, famed for its idyllic beaches and limestone cliffs, and had been trying to confiscate illegally cut timber as part of a personal crusade to stop rampant deforestation.

"If this illegal activity is not stopped, I think before my youngest daughter becomes a young adult and has a family of her own, all the big trees here will be gone," Arzaga, 49, told AFP in February during another mission to confiscate chainsaws from illegal loggers.

Police said Arzaga, who was leading a small group of local officials, was ambushed at the logging site in September. Two brothers from Arzaga's local community have been charged with murder over his killing.

Arzaga belonged to the Palawan NGO Network Inc (PNNI), a non-profit group made up of so-called para enforcers that uses a citizen's arrest law to confiscate equipment that is being used to destroy the island's environment.

Arzaga was the 12th member of the group murdered since 2001.

"The PNNI's environmental enforcement work is an example of concerned citizens willing to risk their lives to save Palawan's precious environment. It's a selfless, courageous task that should be celebrated," said Kyte, from Global Witness.

Nieves Rosento, the mayor of El Nido and a friend of Arzaga's who is struggling with few resources to stop environmental destruction in the area, said the work of PNNI was essential.

"We have a lot of battles here, and they help a lot," Rosento told AFP a day after attending Arzaga's funeral.