Venezuelan opposition leader Maria Corina Machado, who has mostly been in hiding since July 28 presidential polls, led a "Protest for the Truth" in Caracas on Saturday against Nicolas Maduro's disputed claim of having won reelection.

Atop an opposition campaign truck, and surrounded by motorcyclists and cars waving the national flag, she joined hundreds of supporters gathered in the capital in response to her call for mass gatherings in more than 300 cities in Venezuela and abroad.

Earlier, Machado had called for the anti-Maduro movement to "remain firm and united" in the face of threats and violence.

"They're trying to scare us, to divide us, to paralyze us, to demoralize us, but they can't because they are absolutely entrenched in their lies (and) violence," she wrote on X.

Many protesters waved printed copies of election records from their voting stations, which they say prove the opposition won.

Venezuela's National Electoral Council (CNE) proclaimed Maduro the winner of a third six-year term until 2031, giving him 52 percent of votes cast on July 28 but without providing a detailed breakdown of the results.

The opposition says polling-station-level results show its candidate Edmundo Gonzalez Urrutia took more than two-thirds of the vote.

Gonzalez Urrutia replaced Machado on the ballot after she was ruled out of running by institutions loyal to the regime.

"If we keep quiet, this makes no sense," said demonstrator Adriana Calzadilla, a 55-year-old teacher in Caracas.

"This is a criminal government that wants to hold on to power. I smell freedom, I have nothing to fear."

Anti-Maduro protests have claimed 25 lives so far, with nearly 200 injured and more than 2,400 arrested since election day.

Early on Saturday, a heavy security presence took shape in the capital, with two armoured vehicles and 40 motorcycle-mounted troops controlling access to the low-income Petare neighborhood, a few miles from the opposition's gathering point.

Local media reported similar deployments in other areas.

At one of the first overseas demonstrations to get under way Saturday, more than 100 Venezuelans in Australia rallied in Sydney, waving national flags and balloons.

"This is a strong message to our people in Venezuela. We are with you, and we want the world to listen what we are saying," said protest organizer Rina Rivas.

It was unclear if Gonzalez Urrutia, also in hiding, will attend Saturday's march. He last appeared in public at a protest on July 30.

Maduro had called for Machado and Gonzalez Urrutia to be arrested. He accuses them of seeking to foment a "coup d'etat." (AFP)