Venezuela's President Hugo Chavez said on Sunday he will start radiation therapy for cancer in the coming weeks, a treatment that could leave him weakened ahead of his re-election bid on October 7.

In a televised appearance from Cuba, where he is recovering from a third surgery to treat cancer in his pelvic region, Chavez spoke with his cabinet ministers to project an image he is fully in command of the government despite his illness.

He gave few new details about his condition that would squelch rumours he has a life-threatening condition, possibly a metastasis.

In the coming weeks we will start the already announced phase of radiotherapy, Chavez, 57, said wearing a windbreaker with the colours of the Venezuelan flag.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Speaking for more than two hours, Chavez linked up via satellite with his vice president and other ministers presiding over events in Venezuela to inaugurate government projects, like a chicken farm jointly owned with an Argentinean company.

Venezuela's leftist government is on a massive spending push, funded by oil dollars from the coffers of South America's largest crude exporter, to win over poor voters with popular welfare programs, including job training and new housing units.

Chavez said he approved the issue of a bond in local currency for some $2.325 million due between 2015 and 2017 to spend in the agricultural sector, with the participation of a government fund and state oil company PDVSA.

TOUGH CAMPAIGN

The government has been secretive about what kind of cancer the president has. Medical experts say the radiation treatment can take a heavy physical toll.

The side effects may slow down Chavez's gregarious on-the-street campaigning style just as he faces a formidable race against 39-year old opposition candidate Henrique Capriles.

The former state governor won a strong mandate in a primary election last month and is expected to contrast his energetic and youthful image with Chavez's convalescence.

Opinion polls show Chavez, in power since 1999 and omnipresent in the media, still has the edge over Capriles in voter enthusiasm.

Roughly a third of the electorate is still undecided, however, and with no clear successor to carry on Chavez's 21st Century revolution, Venezuelans will be closely watching for signs he has the strength to run a campaign and rule for another six-year term after 13 years in power.

On Sunday he sang songs, laughed with his ministers and said he was reading a lot of books, quoting from a thick volume by Marxist philosopher Istvan Meszaros.

He also said he will be coming back to Venezuela soon, which could mean he will face radiation treatment at home.

I must return in the next few days, God willing. This week, starting today, will not pass without my return to Caracas, Venezuela, Chavez said.

Since arriving in Cuba on February 24, Chavez has been firing off tweets and phoning state TV, which broadcast images meeting his Colombian counterpart earlier this week, in what could be preparation for a triumphant homecoming.

He made his first emotional return from Cuba last June after surgeons removed a baseball-sized tumour from his pelvic area.

He later declared himself completely cured after several rounds of chemotherapy, surprising the nation last month when he said the cancer had reappeared and needed another operation.

(Additional reporting by Marianna Parraga and Mario Naranjo; Editing by Paul Simao)