* President suffering post-surgery complications
* Socialist leader diagnosed with cancer in mid-2011
CARACAS Dec 31 (Reuters) - Venezuelan President Hugo Chavez is in stable condition and spent Monday with his daughters, the cancer-stricken leader's son in law said in an appeal for supporters to ignore rumors about his condition.
Chavez has not been seen in public nor heard from in more than three weeks. The vice president said late on Sunday that the 58-year-old was suffering a third set of complications after surgery in Cuba on Dec. 11, his fourth operation in 18 months.
"Compatriots, DON'T believe in ill-intentioned rumors," Science Minister Jorge Arreaza, who is married to Chavez's daughter Rosa Virginia, wrote on Twitter from Havana where they have been at the former soldier's bedside.
"President Chavez spent the day quietly and stable, accompanied by his daughters."
Chavez has not provided details of the cancer that was first diagnosed in June 2011, leading to speculation among Venezuela's 29 million people and criticism from opposition leaders.
Officials have said that he suffered unexpected bleeding as result of the complex, six-hour operation on his pelvic area, and that doctors then had to fight a respiratory infection, which also caused his latest setback on Sunday.
Chavez's death or resignation for health reasons would upend politics in Venezuela, where his personalized brand of oil-financed socialism has made him a hero to the poor majority but a pariah to critics who denounce him as a dictator.
The president's condition is being watched closely around Latin America, especially in other leftist-run nations such as Cuba, Ecuador and Bolivia which depend on subsidized fuel shipments and other Venezuelan aid for their fragile economies.