In an address on the impact on business of an epidemic which has claimed more than 5,400 lives in west Africa, Machel said the heavy toll was "unacceptable".
"Ebola has exposed the extreme weaknesses of our institutions as governments, countries which are affected were found totally unprepared," added the South African icon's widow.
"It's time Africa began to give real value to human life, in other words African human lives," she told health sector and business representatives.
"We can't continue to be unprepared as we are," she said. "We don't seem to have learned from the HIV epidemic."
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She insisted Ebola could be defeated with "proper and strong health systems".
The African Union, African Development Bank and regional business leaders earlier this month set up an Ebola crisis fund, almost a year after it was first detected in December last year.
Although Machel called the AU's reaction "too late and too little", she commended it for eventually rallying the business community to help curb the spread of the virus.
Southern Africa has so far seen no cases of the virus.