MANILA (UPDATE) - President Rodrigo Duterte's trust and approval ratings went down in the third quarter, according to the latest Pulse Asia survey, amid issues in the country's national penitentiary and police force.

Duterte received a trust rating of 74 percent, an 11-point decrease from last quarter's 85 percent, after dropping in all areas except in his home region of Mindanao.

• 8 out of 10 Pinoys approve of, trust Duterte: Pulse Asia

The survey said that 78 percent of 1,200 Filipino adults approve of Duterte's performance, down by 7 points from the previous quarter's 85 percent.

The drop in the President's ratings came as the Senate investigated alleged irregularities at the New Bilibid Prison operated by the Bureau of Corrections, which also supposedly involves "ninja cops" or policemen who resell seized illegal drugs.

The President has ordered an investigation into Philippine National Police chief, Police General Oscar Albayalde, whom he said is presumed innocent until proven guilty.

• Duterte orders probe on Albayalde over 'ninja cops' allegations
• Duterte demands 'clear proof' Albayalde linked to drugs

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Aside from these, the "significant decline" in the President's ratings may be attributed to the President's approach to the Philippines' maritime dispute with China and government's drug war, according to Pulse Asia President Ronald Holmes.

Duterte in August raised Manila's arbitral win that invalidated Beijing's sweeping claims in the South China Sea, to President Xi Jinping.

• Xi rejects Philippines' arbitral win in South China Sea

"One would be largely our continued dispute with China and the approach the President has taken. We can also say it has to do with the drug war, with more recent issues including the good conduct time allowance problem that emerged within the last month," he said.

The President, however, still enjoys a "significant majority approval," Holmes said.

"Basically 3 out of 4 Filipinos approve and trust the President. Getting to the end of the year, Filipinos are bit more optimistic during the holidays. We don’t know whether they will generate a higher or sustain the approval ratings of the President," he said.

Malacañang, meantime, said the President's ratings are "still high."

"'Di ba nagfa-fluctuate naman talaga 'yan, pero more than 70 percent pa rin eh," Presidential spokesperson Salvador Panelo told reporters.

(Ratings fluctuate, but it's still more than 70 percent.)

The approval and trust ratings of Vice President Leni Robredo also fell to 50 percent from 55 percent and 46 percent from 52 percent, respectively.

Senate President "Tito" Sotto's ratings also went down and received a 72 percent approval rating from last quarter's 77, and a 66 percent trust rating versus 73 percent in the previous quarter.

House Speaker Alan Peter Cayetano, who will only serve for 15 months under a power-sharing agreement with Marinduque Rep. Lord Allan Velasco, received a 64 percent approval rating and a 62 percent trust rating.

Supreme Court Chief Justice Lucas Bersamin, who is set to retire on Oct 18., enjoyed a minimal increase in his approval rating to 42 percent from 41 percent last quarter. His trust rating went down a notch to 34 percent.

The poll, conducted from Sep. 16 to 22, has a ± 2.8 percent error margin.