The controversial procedure could be available to the public for as little as $670 as early as next year.
The test measures microscopic DNA sequences on the tips of human chromosomes called telomeres, believed to be the most accurate signposts to how fast a person ages.
UK researchers claim measuring telomeres will calculate someone's biological age and whether this differs from their chronological age.
Medical experts said the practice was expected to grow rapidly over the next decade, with major implications for life-insurance policies or medical cover.
Some scientists fear the breakthrough may be hijacked by unscrupulous "snake-oil" salesmen, peddling fake or unproven anti-ageing remedies.They also raised concerns about how people may react to a test telling them how old they "really" are.
Telomere expert Associate Professor Tracy Bryan, of Sydney's Children's Medical Research Institute, doubted the test's accuracy, saying a correlation between short telomeres and age-related diseases did not mean it was possible to determine how long a person had to live.
"I think this may lead to unnecessary worry," she said.
Medical ethicist Dr Nicholas Tonti-Filippini also doubted such a test could accurately predict when a person's time was up.
Dr Tonti-Filippini said the best medical technology could do was calculate an individual's average life-span, something that didn't take into account other factors that could contribute to death, such as heart disease or cancer.
"When a person's time is up, it won't be affected by the length of their telomere," he said.