MANILA - Malacañang dismissed fears that going for a constituent assembly "con-ass" as a mode for charter change would be "self-serving" for lawmakers.

Presidential spokesperson Ernesto Abella on Friday told reporters that any results from charter change will not benefit current leaders.

"First and foremost, whatever results will be from the con-con or con-ass, it will be for the benefit of the next generation of leaders, right? It will not be affecting them directly. So being self-serving doesn't really come into play here," Abella said.

Abella has no estimate how much either mode of charter change would cost government.

"We have don't know exactly estimate, but according to DBM [Department of Budget and Management] it's an enormous amount of money," he said.

House Speaker Pantaleon Alvarez on Thursday said President Rodrigo Duterte is now in favor of allowing sitting legislators to amend the Constitution as he eyes a shift to a federal-parliamentary form of government by 2022.

Alvarez said Duterte threw his support behind a constituent assembly during a meeting with him and Senate President Aquilino "Koko" Pimentel III.

"Wag ho kayong mag-alala. Under the leadership of President Duterte, your fears under 'con-ass,' wala po yun. We committed to do it for the country," Alvarez said.

READ: Duterte now for constituent assembly to amend charter: Speaker