MANILA -- Former Foreign Affairs Secretary Albert Del Rosario said Monday that he donated P500,000 to the 22 fishermen who were left adrift for hours near Reed Bank (Recto Bank) after their boat was sunk by a suspected Chinese militia vessel.

Del Rosario, the wealthiest member of the previous administration's Cabinet, told ABS-CBN News that he made the donation "to manifest that we truly care for them (fishermen) and empathize with what has happened."

"May the good Lord hold them close to his bosom," he said in a text message.

Before entering public service, Del Rosario was a businessman whose ventures include insurance, banking, real estate, shipping, telecommunications, consumer products, retail, pharmaceuticals, and food industries.

The former diplomat said he handed his donation to the Department of Foreign Affairs last Wednesday.

The fishermen, who were rescued by a Vietnamese craft, also received P50,000 each from Vice President Leni Robredo, the leader of the opposition, who visited their hometown in San Jose, Occidental Mindoro last Friday.

The Duterte administration earlier gave the fishermen fiberglass boats, sacks of rice, cash assistance, livelihood packages and scholarships for their children.

Beijing said its trawler merely "bumped" into the Philippine boat and tried to rescue the fishermen but was "afraid of being besieged by other Filipino fishing boats".

President Rodrigo Duterte last week approved China's proposed joint investigation into the sinking that he earlier dubbed as a "simple maritime incident."

The plan "defies logic", Del Rosario said earlier Wednesday.

"If there is an offense, you don't ask the offending party to investigate itself... You have one party that is looking for the truth and another party that is out to suppress it so it's not gonna work," he told ANC.