MANILA (Reuters) - The Philippines is paving the way to shift to a federal form of government by 2022, after President Rodrigo Duterte agreed with the leaders of Congress to set up a body to amend the constitution, the speaker of the house said on Thursday.

Duterte, who swept to power in May on a wave of public anti-establishment frustration over crime and poverty, wants to switch from a centralized government to devolve power to long-neglected poor provinces and spread wealth more evenly.

"By granting more, and specific, powers to the state governments, the red tape that leads all the way to Manila will be shaved off, reducing delays and uncertainties inimical to business," House Speaker Pantaleon Alvarez told businessmen.

Duterte met Alvarez, a close ally, and Senate President Aquilino Pimentel late on Wednesday to decide how best to change the nearly 30-year-old constitution, he added.

The aim is for a plebiscite on the constitutional changes to be held along with mid-term elections in 2019, Alvarez said, followed by a transition period until the expiry of Duterte's six-year term in 2022.

The proposal will create 11 to 12 states, lumped together from rich and poor provinces, with greater autonomy.

Duterte, the firebrand former mayor of a southern city, has an approval rating of 91 percent, among the highest recorded in the Philippines, and enjoys the support of a majority of lawmakers in both houses of Congress.

"Right now everything is Manila-centric," said Perry Pe, president of the Management Association of the Philippines, adding that the change had been a Duterte campaign plank.

"I am a believer in devolving powers. I want areas to develop their own systems and to be able to raise productivity."

(Reporting by Enrico dela Cruz and Karen Lema; Editing by Clarence Fernandez)