Maduro intends to hold an election on July 30 to choose a citizens' body called the "Constituent Assembly" to redraw the constitution, a move opponents fear will sideline the legislature.

"The convening of such an assembly risks further polarising the country and increasing confrontation," EU foreign policy chief Federica Mogherini told reporters after EU foreign ministers met to discuss other issues.

"So we believe it would be helpful if the government looked for political gestures to de-escalate tensions, create better conditions for resumption of work towards a peaceful negotiated solution," the top EU diplomat said.

"Suspending the process of putting the constituent assembly into place would be such an important gesture," Mogherini said.

She expressed support for a symbolic mass opposition vote on Sunday against Maduro's plans to rewrite the constitution, saying it showed "there is a willingness from the people in Venezuela to have an urgent peaceful solution to their difficulties."

Mogherini said "all the options are always on the table for political consideration" when asked if the European Union could eventually consider imposing sanctions on Venezuela if Maduro goes ahead with the assembly.

The Venezuela issue was not on the agenda for the EU foreign ministers' meeting but came up when Mogherini answered media questions.

On Sunday, an unofficial plebiscite held by the opposition saw more than seven million of Venezuela's 19 million voters cast ballots, overwhelmingly against Maduro, according to election guarantors from the university community.

Celebrations and cries in the street of "The government is falling!" greeted the end of the vote.