Venezuelan President Hugo Chavez will return to Cuba to begin radiation treatment for cancer on Sunday, but said he was in good shape and would be back home in several days.

Since returning to Caracas from Havana a week ago after a third operation in less than a year to remove a malignant tumour from his pelvis, the 57-year-old socialist leader had been saying he would begin radiation therapy soon.

But until Saturday the president had not revealed whether he would fly back to Cuba or stay in Venezuela for the treatment, which is expected to leave him weaker during his campaign to win a new six-year term at a presidential election on October 7.

Tonight I leave for Havana. I have decided, on the recommendation of my medical team and my political team, to begin the radiation treatment tomorrow, Chavez said during a televised cabinet meeting.

Chavez has dominated Venezuelan politics for the last 13 years, and his illness has shocked voters in South America's biggest oil exporter in the run-up to the election.

Some have questioned how fit he would be to govern if he won, and his treatment is expected to stop him from conducting the kind of man-on-the-street campaign that has worked so well in the past to help him drive forward his leftist revolution.

(Reporting by Daniel Wallis; editing by Eric Beech and Todd Eastham)