Caracas: Venezuelan opposition candidate Henrique Capriles on Monday accused acting president Nicolas Maduro of unfairly using state media and money in his campaign to succeed the late Hugo Chavez.

The accusations come two weeks before voters choose a new president following the death of Chavez, the flamboyant leader who governed oil-rich Venezuela for 14 years and launched a self-styled leftist “revolution.”

“The state media have become a propaganda wing of a political party,” Capriles alleged, referring to the socialist party of 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.

The campaign does not officially begin until Tuesday, but Capriles said Maduro had spent 46 hours on state TV since Chavez’s death on March 5.

Capriles went on to urge the National Electoral Council to be impartial and enforce campaign rules ahead of the April 14 vote.

Communications Minister Ernesto Villegas fired back on Twitter, saying state television had broadcast Capriles’s press conference live “despite his orders to prevent access for journalists” from state media.

Villegas also again invited Capriles to be interviewed on state television, after the opposition candidate denied an earlier request, saying state media is biased against him.

Later on Monday night, Capriles joined a march against insecurity in the country, railing against the government for failing to address the pressing issue.

“There is not a single proposal for the government to defeat violence and give peace to Venezuelans,” Capriles said before a crowd of hundreds of thousands.

In the first three months of the year, Venezuela recorded 3,400 murders, interior and justice minister Nestor Reverol said on Monday on state television.

In 2012, the country saw 16,000 homicides, a 14 per cent increase over the year before, he added, vowing to strengthen security measures.

Unofficial tallies put the figure even higher, with the Venezuelan Observatory of Violence citing 21,000 murders in 2012.

Maduro, 50, formerly served as Chavez’s foreign minister and vice president. Miranda state governor Capriles, 40, lost to Chavez in an October election.

Chavez, who came to embody a resurgent Latin American left while channelling Venezuela’s vast oil wealth into social programmes for the poor, died last month after a long battle with cancer.

During his 14 years in power Chavez developed a vast media apparatus consisting of at least five television broadcast channels, two newspapers and dozens of local radio stations carrying the government’s message.

Maduro leads Capriles by a 20-point margin, according to a poll out Monday by Hinterlaces, which indicated Maduro would win 55 per cent of the vote compared to Capriles’s 35 per cent.

A previous survey on March 19 gave Maduro a similar margin of 18 points.

Maduro insisted the “revolution” was united behind him.

“I trust that people will go to the polls to vote for Maduro because we are like a family that lost its father,” he said.

“The people have united because now it is everybody’s responsibility to continue Chavez’s legacy.”

Some 150 international observers are expected to be on hand for the vote, the electoral council announced on Monday, but they are limited by a 2006 law to providing recommendations on elections.

Referring to the October contest, the Carter Centre, founded by former US president Jimmy Carter and his wife Rosalynn, approved of the electronic voting system but noted the incumbent had an advantage because the government could broadcast lengthy speeches by Chavez and ads praising its own policies, neither of which was considered campaign publicity.