Argentines voted on Sunday in legislative elections that will test support for President Javier Milei's free-market reforms and deep austerity measures and determine whether he has the backing to continue his economic overhaul.

The president's party, La Libertad Avanza, aims to significantly boost its small minority in Congress to increase investor confidence in Milei's vision and maintain the support of U.S. President Donald Trump, who recently provided Argentina with a hefty financial bailout but has threatened to pull away if Milei does not do well.

"Don't give up because we're halfway there," Milei told supporters at a closing campaign event in the port city of Rosario on Thursday. "We're on a good path."

Half of Argentina's lower Chamber of Deputies, or 127 seats, as well as a third of the Senate, or 24 seats, are up for election in the midterm vote. The Peronist opposition movement holds the largest minority in both houses, while Milei's relatively new party has only 37 deputies and six senators.

Election results are expected to come in starting at 8 p.m. ET (0000 GMT).

Milei voted on Sunday morning in Buenos Aires' leafy middle-class Almagro neighborhood and waved to the public but did not give any statements. At voting centers across the city, some residents told Reuters they wanted to continue supporting the president's overhaul.

"Milei is risking it all for a deep change and he needs support because it's not an easy task after years of populism," said Cecilia Juarez, a 22-year-old university student, before voting, referring to the Peronist governments that dominated much of Argentine politics over the last 50 years.

Silvio Caballero, 54, a university professor, was more pessimistic.

"The economic growth is very slow, I don't know when we'll be able to be a first world country," Caballero said. He did not say who he was voting for.

The White House and foreign investors have been impressed by the government's ability to significantly reduce monthly inflation - from 12.8% before Milei's inauguration to 2.1% last month - achieve a fiscal surplus, and enact sweeping deregulation measures.

But Milei's popularity has fallen in recent months due to public frustration with his cuts to public spending and a corruption scandal tied to his sister, who also serves as his chief of staff.

"Milei's adjustment has been done with treachery and cruelty," said Axel Kicillof, the governor of Buenos Aires province, during a closing campaign event for the Peronist opposition coalition on Thursday. "They enjoy each victim of the cuts."

Political experts say that more than 35% of the vote would be a positive outcome for Milei's government and could allow him, through alliances with other parties, to block efforts by opposition lawmakers to overturn his vetoes against laws Milei has said threaten Argentina's fiscal balance.

Maria Laura Tagina, a political scientist at the Universidad Nacional de San Martin, said the Peronist movement will have to fight harder than Milei's party to achieve a "good election" because many more of its seats are up for grabs.

Milei has said he expects a cabinet shake-up after the election that could include members of the centrist PRO party, a frequent ally of the government in Congress led by former president Mauricio Macri. On Monday, foreign affairs minister Gerardo Werthein resigned.

The election will be closely watched by the White House. Trump's potential $40 billion bailout of Argentina includes a signed $20 billion currency swap and a possible $20 billion debt investment facility.

Following the results, many analysts predict a devaluation of the peso, which they say has been overvalued to contain inflation. If Milei's party underperforms, that may result in a sharper foreign-exchange policy adjustment.