Juan Guaido made the plea today near an air force base in capital Caracas, joined by 70 soldiers.
President Nicolas Maduro’s government is now preparing to confront a small group of “military traitors” as the country appears on the brink of all-out war.
Tear gas has been fired Guaido and the crowd, eyewitnesses report.
Guaido said troops who take to the streets would be defending Venezuela’s constitution.
He made the comments a day before a planned anti-government rally and said “the moment is now”.
Guaido added: “The national armed forces have taken the correct decision, and they are counting on the support of the Venezuelan people.”
Around 50 countries including the United States have recognized him as Venezuela’s interim president.
Guaido has been traveling outside the capital, Caracas, more and more in recent weeks to try to put pressure on Maduro to step down.
The defence minister insists that armed forces remain “firmly in defence of the national constitution”.
Vladimir Padrino López added: “We reject this coup movement that aims to fill the country with violence.”
Protests are planned for tomorrow in what could be the “largest march in Venezuela’s history”.