Opposition presidential hopeful Henrique Capriles on Monday said Venezuela's acting president Nicolas Maduro was unfairly using state media and money to support his campaign.
The accusations came two weeks before voters head to the polls to choose a new president following the death of Hugo Chavez, the leftist leader who dominated Venezuelan politics for 14 years before his death last month.
"The state media have become a propaganda wing of a political party" Capriles alleged, referring to Maduro, Chavez's handpicked successor.
In free and fair balloting, candidates are supposed to have the same access and the same rights, Capriles told a press conference.
But Maduro, a former bus driver and union leader, is relying on "all of the state's resources ... and all of the state's power structure" to run his campaign, Capriles charged.
He went on to urge the National Electoral Council to be impartial and enforce campaign rules ahead of the April 14 vote.
Maduro, 50, formerly served as Chavez's foreign minister and vice president. Miranda state governor Capriles, 40, lost to Chavez in October elections.
Chavez, who came to embody a resurgent Latin American left while channeling Venezuela's vast oil wealth into social programs for the poor, died March 5 after a long battle with cancer.