MANILA (Reuters) - Philippine lower house lawmakers voted on Tuesday to convene the chamber as a constitutional assembly, looking to amend the 30-year-old charter and shift to a system of federal government, allowing the president up to two terms in office.

The switch to a federal system was one of the key planks of President Rodrigo Duterte’s election campaign, aimed to remedy what he saw as neglect by a Manila-centric political establishment that has left provinces in perpetual poverty.

In a late afternoon session, Duterte’s allies, who dominate the nearly 300-member house, abruptly terminated debates and voted to convene an assembly to begin changing some constitutional provisions.

Opposition lawmaker Edgar Erice protested against the speed of the decision, describing it as “railroading”.

“They did not even allow a congressman to finish his interpellation and he was run over by the ‘Cha-Cha’ train,” he added.

The majority of lawmakers favor the expansion of the two legislative chambers, longer terms for all elected officials, greater fiscal autonomy for provinces, a prime minister as the head of government, and a separately elected president.

They plan to complete their amendments within two months and hold a referendum in May this year.

A total of 186 lawmakers attended Tuesday’s session.

Roger Mercado, head of the constitutional amendments panel and the sponsor of Tuesday’s measure, said lawmakers will wait for a similar resolution in the upper house before formally convening the assembly.

“Let’s not waste people’s money and time. Let us go ahead and convene already,” Mercado told an earlier session.

The alternative, of creating a special constitutional convention, would cost 11 billion pesos ($218 million), he added.

Senators oppose combining the two chambers to draft the amendments, fearing it will cause a loss of relevance for the normally powerful 24-seat upper house. On Monday, Senator Panfilo Lacson launched a resolution urging the senate to convene a constituent assembly of its own.

The push to change the constitution has been a divisive issue, with critics accusing lawmakers of trying to prolong their stay in office, or of seeking a way for Duterte to stay in power beyond the end of his term in 2022.

Opponents warn it could lead to a repeat of the 1970s-era of late dictator Ferdinand Marcos, saying they are troubled by Duterte’s stated admiration for him, as well as the president’s similar authoritarian traits.

The opposition says the 1987 constitution was drafted to stop that from happening.

Duterte has made clear he has no desire to stay longer than his term and, if anything, would prefer to retire earlier.

Lawmakers have yet to decide on what federal model to adopt, Mercado said. Duterte’s preference is for one similar to that of France.