Russia and China vetoed a US draft resolution calling for the holding of presidential elections in Venezuela and the "unhindered delivery of humanitarian assistance" to the country.
South Africa was voted against by the non-permanent member of the UN Security Council, while nine members of the council, especially the Europeans and Latin Americans, supported it.
Three countries abstained - Equatorial Guinea, Ivory Coast and Indonesia.
While Peruvian Ambassador Gustavo Meza-Guadra, who voted with the resolution, regretted the rejection of the US draft resolution, Russian Ambassador Vasily Nibinza said it would have been an unprecedented decision to "isolate the president" of a state.
"The United States is intransigent in escalating it ... and its aim is to change the regime," he said.