MANILA (2ND UPDATE) - Presidential Spokesperson Harry Roque on Thursday said President Rodrigo Duterte might make good on his promise to step down if former Senator Ferdinand "Bongbong" Marcos Jr. wins his poll protest against Vice President Leni Robredo.

“He has said he thinks [former] senator Bongbong Marcos is one of the better qualified leaders to succeed him. If there’s development and he (Marcos) will win the protest and he becomes vice-president, yes. He (Duterte) will make true his word,” Roque said in a Palace briefing.

Duterte, now 73 and the oldest to be elected Philippine President, on Tuesday said he is “tired” and would like to relinquish his post as he expressed frustration over rampant corruption in government and persistence of the illegal drug trade.

But the President said he is not amenable to following the Constitution when it comes to succession.

He said Robredo may not have what it takes to lead the country and that the military, or the likes of Marcos and Senator Francis Escudero, are better suited for the job.

• Duterte prefers Bongbong, Chiz as replacement instead of Leni

If Marcos wins his poll protest against Robredo and becomes Vice President, he will become the constitutional successor to the presidency.

Marcos has asked the Presidential Electoral Tribunal to invalidate Robredo’s poll victory in 2016. The vice-president beat the former senator by 263,473 votes. A recount is ongoing.

The former senator claims the automated polls were rigged by Robredo’s Liberal Party, then the ruling party.

Robredo’s camp has dismissed Marcos’ allegations and asked him to accept defeat.

Marcos' father, the late strongman Ferdinand Marcos, had led a dictatorial regime marked by repression of free speech, human rights abuses, and plunder, among others.

The Marcos family is still facing several cases in court over alleged abuses but continues to command loyal following.

Duterte, a known friend of the Marcos family, allowed the late dictator's burial at the Libingan ng mga Bayani in November 2016, in rites held hurriedly away from public eye.

His administration has also moved to abolish the Presidential Commission on Good Government, an agency tasked to recover the Marcos' ill-gotten wealth.

• No ‘revisionism’ in proposed PCGG abolition - Palace

Duterte's late father Vicente served in Marcos' pre-martial law cabinet.