Some 49 percent of 18- to 24-year-olds "say they are likely to vote later this month, while 16 percent say they won't and another 35 percent haven't yet decided," according to the survey by the Johannesburg-based Ichikowitz Family Foundation.
South Africans vote in parliamentary elections on May 29, in what is set to be the tightest vote since democratic rule was introduced at the end of apartheid.
Frustration with the ruling African National Congress (ANC), accused of corruption and mismanagement, is widespread.
Graft, high unemployment and gender-based violence rank as the top causes of concern among the younger generation.
As a result, 48 percent of young people have expressed an interest in leaving the southern African country— with 85 percent saying they are "very concerned" about graft.
The foundation conducted more than 1,000 face-to-face interviews with 18- to 24-year-olds across the country.
Three-quarters of respondents said they believed South Africa was headed in the wrong direction 30 years since the dawn of democracy.
Only 40 percent of young people agree that the government has been "successful both in creating a non-racial society and addressing racial inequality," the study said.
Forty-nine percent believe the government has been unsuccessful in ending apartheid.
After three decades in power, the ANC risks losing its absolute majority and being forced to share power in a coalition government.
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