The government spokesperson and minister of information Dr James Nsaba Buturo described the rumour as "irresponsible".
Buturo said a cabinet meeting yesterday had resolved to deal ruthlessly with the purveyors of the rumours who seek to take advantage of such national tragedies. He said the rumours had offended the president, the families and everybody.
"People in Khartoum, Juba have been calling about these false reports," he said.
Dr Garang died last week in a helicopter crash as he returned home after a two-day visit to President Yoweri Museveni. He was travelling in the presidential helicopter piloted by Col Peter Nyakairu and six other Ugandan crew members who all perished in the crash. Government says the plane crashed due to bad weather in the areas of Kidepo valley inside the Sudan.
Since the crash several conspiracy theories have been advanced as some people refuse to accept that Garang’s death was a normal accident. The Sudan government retained the bodies of the Ugandan crew members to allow investigations.
Buturo said that three separate teams of experts had been commissioned to carry out detailed investigations into the crash.
These include a Uganda government team, another from the Sudan government and an international team comprising experts from the United States, the United Nations, Russia, which manufactured and serviced the MI72 helicopter (VIP-version), Kenya, Uganda and Sudan.
Buturo said the reports of the investigators will clear the air about the actual cause of the deaths. He said the various teams of experts are carrying out their investigations independently and would therefore not be compromised.
"Government has been bold to invite these people and the reports will be made public," he said.