The electoral authority delivered petition sheets to the opposition alliance on Tuesday, officials and lawmakers said.

"An irreversible process of change has begun in Venezuela," opposition leader Julio Borges announced.

Previously, the electoral commission rejected three opposition requests to provide the forms, sparking fierce criticism. In response, regime opponents threatened to lead a protest march to the election board.

Long road to ousting Maduro

With the necessary paperwork now in place, the opposition can continue their bid for a referendum to remove Maduro from office.

However, that path has many more obstacles, and no guarantee of success.

First, the opposition needs to gather some 200,000 signatures to schedule a formal drive for its next petition. This later petition requires signatures from some 20 percent of the electorate, or four million people, to warrant a referendum. Even then, Maduro would not be removed if the number of people voting against him was under 7.6 million, which is the number of votes he received in the 2013 election.

Additionally, if Maduro were removed after the end of this year, there would be no new elections. Instead, the country would be ruled by Maduro's vice president until 2019.

Maduro's predecessor Hugo Chavez survived a recall referendum in 2004.

Supreme Court halts opposition push

The opposition won parliamentary elections in a landslide last December. However, Maduro's political allies dominate many state institutions, and regime opponents accuse them of trying to protect the president.

On Monday, Venezuela's Supreme Court blocked a move by the opposition to shorten Maduro's mandate, even before it was formally proposed.

The court ruled that the constitutional amendment shortening the six-year term was viable, but it could not be applied retroactively.