By Brian Ellsworth and Diego Oré
CARACAS (Reuters) - Venezuela is projecting a drastic set of migration patterns in months leading up to the pivotal Dec. 6 parliament vote: a fiercely opposition district of the capital will lose a quarter of its population while pro-government suburbs will swell 5 percent.
The projection led the elections authority this year to take one parliamentary seat away from affluent anti-government areas of Caracas and add one to the working-class Socialist Party bastion of Los Valles del Tuy outside the capital.
Government critics say there is no evidence of such an improbable population shift.
"This is a form of electoral engineering meant to move a legislator toward a population that they control - and to take one away from the opposition," said opposition activist Liliana Hernandez of party Un Nuevo Tiempo (A New Time).
Critics say authorities are trying to tilt the vote toward the Socialist Party, which could lose control of parliament as President Nicolas Maduro's government struggles under a collapsing state-led economic system.
They say the government has shuffled districts, devised confusing ballots to help its candidates and declared states of emergency in border regions to crimp opposition campaigns. There are also long-running complaints over Socialist Party campaigns using state resources, and inadequate international observation.
Any minor leg up could be crucial for Maduro, who is struggling to maintain the unique brand of Latin American populism forged by late socialist leader Hugo Chavez and kept afloat by a decade of bountiful oil revenue.
A loss could limit Maduro's capacity to channel state resources toward political allies and could embolden adversaries to seek a recall referendum next year.
Maduro denies that his party has gamed the system, and says opposition leaders are complaining so they can refuse to recognize adverse results, which the opposition did in 2004.
"We have a great advantage, and we can say it without false modesty: we are better than they are," Maduro told an auditorium of red-shirt-clad party activists in October.
Even after the changes, the Socialist Party faces a tough election.
Venezuelans are exasperated by snaking supermarket lines and chronic product shortages. Inflation is believed to be in the triple-digits. A shrinking economy has precluded the traditional strategy of showering voters with subsidized goods.
Nationwide polls show voters are more than twice as likely to back opposition candidates than those of the Socialist Party, according to surveys between July and September.
But no pollster has published a comprehensive study based on surveys in each electoral circuit, which experts say is the only accurate measure for this type of vote.
"SMUGGLING OF LEGISLATORS"
Figures released by the National Statistics Institute and the National Elections Council show the population of Caracas' most affluent areas will decline 128,000 by the end of the year, then rise 134,000 by next June.
Neither agency responded to requests for comment.
The area in question includes the upscale municipalities of Chacao and Baruta, focal points of more than three months of anti-government protests in 2014 that left 43 dead.
Officials have suggested that the population of pro-government suburbs has increased due to state-backed housing programs and thus need another parliamentary seat.
Opposition sympathizers have dubbed it "smuggling of legislators" or "bachaqueo de diputados," using the popular term for contraband of state-subsidized groceries by smugglers who take the products across the border to neighboring Colombia.
The booming business of trafficking goods to Colombia led Maduro in August and September to put all municipalities adjacent to the border under a state of exception, a national security measure that can limit public meetings.
This could allow officials to restrict campaigning in states where the government has historically been the weakest, such as the convulsed border state of Tachira, birthplace of the 2014 protests.
Critics accuse Socialist Party allies of posing as opposition forces on the ballot to sow confusion and drain votes from the opposition coalition.
The party MIN Unity flies banners with the campaign slogan "We are the opposition," but its electoral lineup tells a different story: its best-known candidate is Socialist Party legislator William Ojeda.
Once part of the opposition coalition, MIN Unity was kicked out in August. Opposition leaders suspected it had become a pawn of the government in the wake of a Supreme Court ruling that ordered it to replace its leaders.
A MIN Unity representative insisted the party does in fact oppose Maduro, describing Ojeda's candidacy as a "mistake."
But other MIN Unity candidates have fueled suspicions the party seeks to confuse voters.
Ismael Garcia, a 28-year-old parking lot attendant with no evident political experience, was registered at the last minute as a MIN Unity candidate.
His name will appear side-by-side on the ballot next to an opposition candidate with more than 30 years of political experience: a man also named Ismael Garcia.
(Reporting by Brian Ellsworth; Editing by Alexandra Ulmer, Andrew Cawthorne and David Gregorio)