Argentine voters punished the country's two main political forces in a primary election on Sunday, pushing a rock-singing libertarian outsider candidate into first place in a huge shake-up in the race toward presidential elections in October.

With some 90% of ballots counted, far-right libertarian economist Javier Milei had 30.5% of the vote, far higher than predicted, with the main conservative opposition bloc behind on 28% and the ruling Peronist coalition in third place on 27%.

The result is a stinging rebuke to the center-left Peronist coalition and the main Together for Change conservative opposition bloc with inflation at 116% and a cost-of-living crisis leaving 4 in 10 people in poverty.