Venezuelan President Nicolas Maduro and his opponents face a crucial showdown on Thursday as the country's opposition calls the first national strike since the 2002 stoppage that failed to topple Maduro's predecessor, Hugo Chavez.
The majority-backed opposition want Venezuelans to close businesses, halt transport and barricade streets as part of a civil disobedience campaign they have called "zero hour" to try and end nearly two decades of Socialist Party rule.
Student and transport groups said they would heed the call and many small businesses vowed to stay shut. Neighbours coordinated blocking off streets and families planned to keep children behind doors in case of trouble.
"I've no doubt Venezuelans will paralyse the nation in rebellion," opposition lawmaker and street activist Juan Requesens said.
The strike is planned to continue for 24 hours starting at 1100 GMT (6 am) on Thursday across the oil-producing nation.
Largest business group avoids full endorsement
The country's largest business group, Fedecamaras, has cautiously avoided full endorsement of the strike but its members have told employees that they won't be punished for coming to work. Fedecamaras played a central role in the months-long 2002-2003 strike that Chavez's political rivals and opponents in Venezuela's private business sector orchestrated in an attempt to topple him.
Chavez emerged from the strike and exerted control over the private sector with years of expropriations, strict regulations and imports bought with oil money, meant to replace local production. Business groups estimate that 150,000 Venezuelan businesses have closed over the last 15 years.
"This is a work stoppage by civil society. He who wants to work, work. Who wants to stop, stop," said Francisco Martinez, the president of Fedecamaras.
Private companies to join strike will be punished
Government-run industries will remain open and Labor Minister Nestor Ovalles said the Maduro administration would punish private companies that close in sympathy with the strike.
"We won't allow, and we'll be closely watching, any disruption that violates the working class' right to work," Ovalles said. "Businesses that join the strike will be punished."
The business group's incoming president, economist Carlos Larrazabal, said the strike would be of limited duration to avoid worsening Venezuela's already dire shortages of food and other basic products.
"Inventory levels right [now] are very precarious," Larrazabal said. "If the supply chains are affected more than they are right now, we could have a bigger problem."
However, the Venezuelan Workers' Confederation, a labour coalition with ties to the opposition, said at least 12 of its 20 member organisations across the country had decided to join the strike. Transportation workers in the capital, Caracas, also said they would participate.
Transportation services will not work
"There's an appeal to the conscience of the Venezuelan people," said Pedro Jimenez, head of a major transport workers' union. "There won't be transportation services."
More than 24 hours before the start of the strike, neighbourhood groups across Caracas were setting up roadblocks of tree branches and tyres to protest Maduro's plans to change the constitution, irritating some residents.
"The government jails the people who protest and those who are protesting are caging the rest of us. It's unfair," said Maria Sandoval, a 27-year-old medical secretary.
But those manning the roadblocks said they had no plans to stop until Maduro fell.
"We have been blocking the streets since yesterday and we will do it all week," said protester Ester de Moreno. "We will continue doing this until this man leaves."
Venezuela's opposition is also demanding freedom for more than 400 jailed activists, autonomy for the legislature, and foreign humanitarian aid.
Some 100 people have died in anti-government unrest since April.