Venezuelan President Nicolas Maduro has ordered the army into the streets as the South American nation braces for what his opponents vow will be the "mother of all protests" on Wednesday.

Mr Maduro, who has faced violent protests over recent moves to tighten his grip on power, ordered the military to defend the leftist "Bolivarian revolution" launched by his late mentor Hugo Chavez in 1999.

"From the first reveille (on Monday morning), from the first rooster crow, the Bolivarian National Armed Forces will be in the streets... saying, 'Long live the Bolivarian revolution,'" Maduro said Sunday night in a televised address.

State TV showed images of army units marching in the streets of the capital, Caracas, as Defense Minister Vladimir Padrino watched.

However there was no sign of soldiers on patrol in the capital this morning.

Venezuela has been rocked by two weeks of unrest since Mr Maduro's camp moved to consolidate its control with a Supreme Court decision quashing the power of the opposition-majority legislature.

The court partly backtracked after an international outcry, but tension only rose further when authorities slapped a political ban on opposition leader Henrique Capriles.

Five people have been killed and hundreds wounded in the ensuing protests as riot police clashed with demonstrators.

Mr Maduro's opponents have called for a massive protest Wednesday, a national holiday that marks the start of Venezuela's independence struggle in 1810.

The president's supporters have called a counter-demonstration the same day.

It is a touchy date in Venezuela, where Chavez and Mr Maduro have built a politics of populist, left-wing nationalism around the struggle for independence from colonial Spain and its hero, Simon Bolivar.

Mr Maduro is fighting off the centre-right opposition's efforts to force him from power amid an economic crisis that has sparked severe food shortages, riots and looting.

Opposition leaders have urged the military - a pillar of Mr Maduro's power - to turn on the socialist president.

Mr Maduro denounced his opponents as "traitors" and called the new deployment a sign of the military's "honor, unity and revolutionary committment."

The defense minister vowed the army would show its "fighting spirit ahead of April 19," but said the deployment was "a call to peace."

"We don't want confrontation," he said.