(Bloomberg) -- El Salvador’s President Nayib Bukele is seeking to expand his power in Congress with voters heading to the polls Sunday in a legislative election that could also pave the way for an International Monetary Fund program.

More than 5 million Salvadorans are registered to vote for new members of the 84-seat legislative assembly. Polls suggest Bukele’s Nuevas Ideas party will win a majority of seats and may come close to a 56-seat qualified majority required for external borrowing authorization.

Investors are betting that with a strong result, the government will seek an IMF program that would include fiscal austerity to reign in a deficit that widened to more than 8% of GDP last year. Such a program would require approval from two-thirds of congress.

A big victory on Sunday could also set the stage for constitutional changes, a worrisome development for critics who see Bukele as already sliding toward authoritarianism.

Why El Salvador Vote Is and Isn’t About Its President: QuickTake

Vice President Felix Ulloa has said he hopes to present constitutional reforms to congress later this year, which may include changes to presidential term limits. Under current law, reforms would require approval by two consecutive legislatures, meaning not until 2024.

Polls open at 7 a.m. local time and close at 5 p.m. Initial results are expected Sunday night, but a new digital counting system may delay final tallies.

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