The intensive care ambulance broke down two weeks ago when Mandela was being rushed to a Pretoria hospital, leaving him stranded for 40 minutes.
The former South African president was transferred to another military ambulance for the remainder of the 50 minute journey between Johannesburg and the Medi-Clinic Heart Hospital.
Presidential spokesman Mac Maharaj said: 'All care was taken to ensure that former president Mandela's medical condition was not compromised by the unforeseen incident.'
Doctors treating Mandela were satisfied that he suffered no harm during this period, Mr Maharaj added.
Today's statement on Mandela's health shows that little has changed with the anti-apartheid hero's condition since his admission to hospital.
Mandela, who became South Africa's first black president in 1994, was rushed to the Pretoria hospital early on June 8 with a recurring respiratory infection.
It was claimed yesterday that Mandela is unresponsive and his immediate family is now discussing whether to withdraw treatment.
He has been in hospital for two weeks battling the infection, but previous statements have indicated that Mr Mandela’s health is improving.
According to a new source, Mr Mandela’s liver and kidney functions are down to 50 per cent and he has not opened his eyes for days.
Support: Children's get-well wishes are taped to the wall outside the Mediclinic Heart Hospital
He has also had two recent procedures, one to repair a bleeding ulcer and another to insert a tube into his body, CBS News reports.
This information indicates that Mr Mandela’s situation is much more much more serious than has been reported by South African authorities.
In an interview last week, South African president Jacob Zuma said Mr Mandela was responding better to treatment.
Marking the 49th anniversary of the sentencing of the former president to life in prison in 1964, last Wednesday Mr Zuma said: ‘We are very happy with the progress that he is now making following a difficult last few days.’
Following the interview with the ANC leader, a government spokesman told local radio that Mr Mandela remained in a 'serious but stable' condition.
As recent as Thursday, one of Nelson Mandela’s grandsons said he hoped Mandela would be discharged shortly as his health was improving.Family worries: Winnie and Zindzi Mandela, ex-wife and daughter of Nelson Mandela, pictured with an unidentified man at the hospital last week, are said to be discussing whether to continue the 94-year-old's treatments
‘Positively we can say that he has been getting better and better each day and hopefully he'll be coming home soon,’ Ndaba Mandela told South African newspaper The Star.
Mandela's history of lung problems dates back to his time at Robben Island prison near Cape Town. He was released in 1990 after 27 years and went on to serve as president from 1994 to 1999.
His hospitalisation is the fourth since December.