Venezuelan President Hugo Chavez is being treated for "respiratory deficiency" after complications from a severe lung infection, his government has said.

"Chavez has faced complications as a result of a severe respiratory infection. This infection has led to respiratory deficiency that requires Commander Chavez to remain in strict compliance with his medical treatment," Ernesto Villegas, the Venezuelan information minister, said on television on Thursday night.

The statement pointed to a deepening crisis for the ailing 58-year-old president, who has not been seen or heard from since his December 11 operation in Cuba, and raised the possibility that Chavez might be breathing with the assistance of a machine.

But the government did not address that question and did not give details of the president's treatment.

Chavez's government expressed confidence in his medical team and condemned what it called a "campaign of psychological warfare" in the international media regarding the president's condition.

Officials have urged Venezuelans not to heed rumours about Chavez's condition.

In its latest statement, the government didn't point to any particular rumours but said "this campaign aims ultimately to destabilise the Bolivarian Republic of Venezuela... and end the Bolivarian Revolution led by Chavez".

Venezuela's opposition has demanded that the government provide more specific information about Chavez's condition.

Chavez has undergone four cancer-related surgeries since June 2011 for an undisclosed type of pelvic cancer. He has also undergone chemotherapy and radiation treatment.

He was re-elected in October to another six-year term, and two months later announced that the cancer had come back.

Source: Agencies