Early results in Argentina's legislative elections on Sunday showed a landslide victory for President Javier Milei as voters overwhelmingly backed his free-market reforms and deep austerity measures, providing a strong boost for the libertarian leader to continue his economic overhaul.

The president's party, La Libertad Avanza, scored 41.5% of the vote in Buenos Aires province compared with 40.8% for the Peronist coalition, according to official results. The province has long been a political stronghold for the Peronists, marking a dramatic political shift.

Nationwide, La Libertad Avanza got 64 seats in the House of Deputies, up from 37, according to government figures.

Milei was aiming to boost his small minority in Congress and maintain the support of U.S. President Donald Trump, whose administration recently provided Argentina with a hefty financial bailout but has threatened to pull away if Milei did not do well.

Half of Argentina's lower Chamber of Deputies, or 127 seats, as well as a third of the Senate, or 24 seats, were 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.

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 had 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.

Political experts said 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.

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.

The election will be welcome news to 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.

Bonds and stocks are expected to rally on Monday as markets open, as the result gives Milei the votes and political capital needed to accelerate his reforms.

Following the results, many analysts predict a devaluation of the peso, which they say has been overvalued to contain inflation.