MANILA - President Rodrigo Duterte's election win came with a mandate from voters to declare a revolutionary government when necessary, which is allowed under the Constitution, his chief legal adviser said Friday.

The 1987 charter allows such a government "when there are forces bent on destroying" it, said Secretary Salvador Panel, the chief presidential legal counsel.

"The electorate factored that in and when he was voted overwhelmingly, the electorate gave him the overwhelming mandate to declare a revolutionary government if there is a need for that," Panelo said.

Asked which provision of the Constitution explicitly authorized the president to do this, Panelo cited the section stating that "the prime duty of the government is to serve and protect the people."

"There is a constitutional mandate for that," he said.

Lawyer Christian Monsod, who was among those who drafted the 1987 constitution, earlier said Duterte was "not voted by our people to be a dictator."

But Panelo said Duterte gave a "notice to the public" when he discussed the possibility of a revolutionary government while campaigning for the presidency.

Duterte's popularity remains high despite widespread criticism over his drug war, which was supported by nearly nine out of 10 Filipinos.

But high survey ratings do not mean public support for his revolutionary government, said Ramon Casiple, executive director of the Manila-based think tank Institute for Political and Electoral Reform.

"It's not (a matter of) survey question, by the way. It's the real politics on the ground," Casiple told ANC's Early Edition Friday.

Duterte's concern over a supposed destablization plot is driven by "paranoia" and forming a revolutionary government will be tantamout to a "constitutional coup," said former legislator Teodoro Casiño of the anti-Duterte group, Movement Against Tyranny.

"To have a revolutionary government, you need a revolution. So where is Duterte's revolution? Wala e (There's none)," Casiño said.