A political analyst believes "true believers" will not abandon presidential candidate Rodrigo Duterte despite his controversial remarks about the rape-slay of an Australian missionary.

Speaking to Mornings@ANC, University of the Philippines political science Prof. Aries Arugay said a lot of Duterte's supporters are "true believers" who can balance out the tough-talking mayor's rape remarks with their overall image of Duterte.

"I do think that this is something serious and should be addressed but at the same time whether it will impact the elections, I highly doubt it because if you take a look at the...strength of support for Duterte, you could see that he really has a constituency,” Arugay said.

He noted that Duterte's remarks about the rape prove to supporters that he "is not a perfect candidate."

"He's not a polished candidate and he's just revealing his humanity and all and even the not so good, the very bad side of humanity that is common to all politicians," he said.

Duterte has come under fire for his remarks over the gang rape and killing of 36-year-old Jaqueline Hamill, a missionary from Sydney, Australia. Hamill was one of several "prayer warriors" taken hostage by Federico Pugoy and other inmates inside Davao Metrodiscom in 1989.

In a campaign rally on April 12 in Quezon City, the tough-talking mayor described the missionary as very beautiful and likened her to an American actress.

"T***a, sayang. Ang napasok sa isip ko, ni-rape nila. Pinagpilahan nila. Nagalit ako kasi ni-rape. Oo, isa rin yun. Napakaganda. Dapat ang mayor muna ang mauna," he said, drawing laughter from his supporters.

WATCH: Duterte jokes about raped Australian woman

In an interview, Duterte admitted making those remarks in 1989 but said he was not joking but merely narrating what happened then. A total of five hostages and 16 prisoners were killed in the hostage crisis including Pugoy and Hamill.

"In my utter anger, gutter language yan eh. Salitang kanto. Nung binuksan ko, o ito, galit ako nagsasalita. Ang ganda-ganda pa, mukhang artista galing Amerika. P***a, naunahan pa ako. Patayin mo lahat! Sa galit yun. I was not joking," he said.

He added: "I am sorry to the Filipino people. It's my style. It's my mouth, I said it in the heat of anger but listen to the story behind. Wag kayong basta pa-ambak ambak yan."

"Huwag kayong makinig sa bunganga ko kasi ang bunganga ko talaga bastos. Kasi lumaki ako sa neighborhood na puro bastos. Sinasabi ko sa inyo, mahirap lang kami."

Duterte says sorry to Filipinos; 'rape remarks not a joke'

In the interview, Arugay said Duterte's remarks could be seen as a major issue in the elections since the president is the head of state and represents the country in the international scene.

He said the remarks could also spark debate on Duterte's character and if people are still willing to see if he will change.

The professor said Filipino voters sometimes have a double standard "in the sense that they want a man of action, a pragmatic leader that would cut corners if it's possible to get things done and not think about whether it is nice, whether the means adopted were courteous or polite."

"At the same time, we wanted someone we could look up to, that we could be proud of."

Arugay said the context of the May presidential election is that there is an increasing discontent in the status quo and the lack of decisive leadership.

"There’s an increasing dissatisfaction about the lack of governance, the lack of decisive leadership and when you have a candidate that says I am here to provide leadership, even if the details are still circumspect, we could see that people cling to that, people might not look into the flaws and all but see that this is a leader that we could hope for,” he said.

He added, with many Filipinos employing the process of elimination in choosing a candidate, Duterte's branding of leadership is keeping him as a viable option.

“A lot of Filipino voters sometimes vote with the process of elimination, and I think this is where supposedly they could opt to support Duterte,” he said.

"If there will be a fallout and Duterte's campaign is not able to manage it successfully, one way is to play the class card and say this is something coming from an ordinary Filipino."

He said Duterte's rivals could also use the controversy to show that the mayor "does not seem to have the right temperament or the right sophistication for the presidency."

"He might be doing good as the mayor of Davao but the national arena and the international scene is a totally different ball game," he added.

He also said Senator Grace Poe might benefit from the controversy since a Pulse Asia survey showed she is the top second choice for voters if they cannot pick their first choice.

"Grace Poe seems to still have that mix of change in continuity. So in a sense, the Grace Poe campaign can still appeal to the decency of moderation. If you want a candidate that's moderate, that's in the middle, that's not too radical but at the same time not too attached to the status quo, then she could portray herself as that."