Venezuela opposition challenges Maduro with unofficial referendum

President Nicolas Maduro's foes announced plans on Monday for an unofficial referendum to let Venezuelans have their say on his plan to rewrite the constitution and the opposition's alternative push for an election to replace him.

The opposition, starting a fourth month of street protests against the socialist government it decries as a dictatorship, will organize the symbolic vote for July 16 as part of its strategy to delegitimize the unpopular Maduro. 

Venezuelans will also be asked their view on the military's responsibility for "recovering constitutional order" and the formation of a new "national unity" government, the Democratic Unity coalition announced. 

"Let the people decide!" said Julio Borges, the president of the opposition-led National Assembly, confirming what two senior opposition sources told Reuters earlier on Monday. 

The opposition's planned vote, likely to be dismissed by the government, would be two weeks ahead of a planned July 30 vote proposed by Maduro for a Constituent Assembly with powers to reform the constitution and supersede other institutions. 

"The government is trying to formalize dictatorship," said opposition leader Henrique Capriles, warning the South American OPEC nation was approaching "zero hour". 

According to a recent survey by pollster Datanalisis, seven in 10 Venezuelans are opposed to rewriting the constitution, which was reformed by late leader Hugo Chavez in 1999. 

Opponents say Maduro's plan is a ruse to consolidate the ruling Socialist Party's grip on power and avoid a conventional free election that opinion polls show he would lose. A presidential vote is due by the end of 2018.