On Wednesday, Guaido declared himself acting president during an opposition rally in Caracas which Maduro described as an attempted coup.
The US has pushed for Guaido to be recognised, taking the matter urgently to be discussed in the security council later on Saturday in New York.
South Africa’s position is expected to assist Russia who are tipped to fight hard against the US-sponsored motion.
Russia, supported by Bolivia, Iran, Cuba, Nicaragua and Turkey have been vehement in their bid not to recognise the opposition government in Venezuela.
South Africa only assumed its seat on the security council earlier this month and the emergency meeting will be the first indicator of which side South Africa leans towards.
Sisulu said Maduro was the democratically-elected president and South Africa recognises him.
“Anything else we find irregular, and that is a position we are going to put across at the UN security council,” she said.
Sisulu also said that Pretoria was still watching developments in that country closely.