"Don't take part and leave the streets empty," said a statement issued by the Democratic Unity Roundtable (MUD), the main opposition coalition, which said it would be a clear sign "rejecting Maduro's regime and electoral fraud."
There are only two challengers running against Maduro, both former supporters of the late Hugo Chavez supporters who have distanced themselves from the current government.
Maduro's only serious opponent is Henri Falcon, a 56-year old former mayor and state governor who has already rejected MUD's calls for a boycott. The other candidate is a little-known evangelical pastor called Javier Bertucci.
"We continue to call on Mr Falcon to refuse to be a part of this farce," opposition deputy Delsa Solorzano told reporters.
Henry Ramos Allup, former president of the National Assembly, said the number of people expected to boycott the vote was "dramatic" with the latest polls suggesting it could be as high as 60%.
Debt-ridden Venezuela is living through one of its worst crises in decades, which the International Monetary Fund has described as one of the worst in modern history.
Despite having huge reserves of oil, the nation has been ravaged by hyperinflation, scarcities of basic food and medicine, and skyrocketing violence that has forced nearly a million Venezuelans to flee.
Even so, Maduro's reelection looks very likely in the absence of any real rival to his authority.
If the vote goes ahead as planned, it looks set to further isolate Maduro and his government.
Last month, the United States and more than a dozen Latin American countries warned Venezuela that its presidential election would be seen as illegitimate by the region unless it restored democratic standards.
In a statement at the Summit of the Americas, Washington and the 16-nation Lima Group which counts Latin America's biggest economies, said the poll would be "void of legitimacy and credibility" if it went ahead under current conditions. – Rappler.com