Tens of thousands of Venezuelans marched in Caracas Thursday to rally opposition to a constitutional referendum that would end term limits on the presidency. In Caracas, VOA's Brian Wagner reports the Sunday vote may be a key test of support in President Hugo Chavez.

People demonstrate during closing rally against constitutional amendments promoted by Venezuelan president Hugo Chavez, in Caracas, 20 Nov 2007

Many of the marchers wore blue shirts and carried signs calling for voters to cast "no" ballots against President Hugo Chavez's reform plan. The rally on a plaza in central Caracas was the last in a series of recent marches led by university students and government opposition groups before the Sunday vote.

Opponents of the 69-point plan say it will place too much control in the hands of Mr. Chavez, but the president argues the reforms are needed to strengthen the people's voice in government. One marcher, recent university graduate Desiree Pachecho said she fears the reforms will take away the people's rights.

Pacheco says the reforms will limit access to government institutions, restrict property rights and the ability for a person to do and say what they feel.

Opposition members expressed confidence they would prevail on Sunday, partly based on recent opinion polls suggesting the "yes" vote would fall short of the 60 percent needed. They also say many long-time Chavez supporters plan to vote against the reform.

Government supporters have campaigned heavily in recent weeks, placing red banners that ask people to vote "yes" around Caracas, and running television advertisements. At a press conference, Telecommunications Minister Jesse Chacon said the official campaign aimed to engage people directly about the reform proposals.

Chacon says officials are not concerned with newspaper predictions and opinion polls, only the actions of the Venezuelan people.

If the opposition vote wins on Sunday, it would mark the first time Mr. Chavez has been defeated at the ballot box since taking office in 1999. The prospect has prompted some opposition members to allege the government may seek to manipulate the results. Cultural director Maria Fernanda Urrutia says she has concerns about the final outcome.

Urrutia says she is confident the opposition vote will prevail, but she is not confident in Venezuela's electoral institutions.

Government officials have rejected allegations of fraud, and say they will accept the people's decision.