Critics say the election is a farce as Maduro’s main rivals remain barred from standing and a compliant election body is bound to favour the socialists.
The opposition Democratic Unity coalition estimated at least 1 million people took part in the protest.
If Maduro loses a referendum this year, the election council would call a new presidential vote – which polls indicate he would likely lose.
The Democratic Unity coalition has ramped up its push to oust Nicolas Maduro amid a worsening economic crisis, but says the government-leaning electoral body is intentionally delaying the verification of signatures in favour of the referendum.
The Democratic Unity coalition (MUD) gathered far more than the required 1% of voters’ signatures, or nearly 200,000, needed to trigger the next phase of a recall referendum.