The study has sparked renewed debate over robotically assisted surgery, and over how much surgeons should be obliged to tell patients about their success rates.
However, the pioneers of robotic surgery in Australia have defended the procedure, saying the research was flawed.
In the paper, the researchers compared the long-term results of "minimally invasive" prostate surgery, which is usually performed using robots, with old-fashioned "open" surgery.
It found that with robotic assistance, men left hospital a day earlier and they were 10 times less likely to need a blood transfusion.
However, more than twice as many (4.7 per cent) suffered "genitourinary" complications.
Almost a third more (16 per cent) were diagnosed with urinary incontinence, and the rate of erectile dysfunction rose by 40 per cent (to 27 per cent).
Professor Simon Chapman, a public health expert from the University of Sydney, said the study casts strong doubts on the claims made on behalf of the robots by proponents such as the Epworth Hospital's Tony Costello.
The Epworth, in Richmond, pioneered robotic-assisted surgery in Australia in 2003, and now runs two of the country's five da Vinci robots.
"Professor Costello's website says the use of this procedure may reduce impotence and urinary incontinence. The use of the word 'may' is very important. Obviously, it may not, either," The Age quoted professor Chapman as saying.
"Men are in an enormously vulnerable position. They are not in a position at all to adequately evaluate the claims put to them by a doctor. The issues of urinary incontinence and sexual impotence are really very important for a lot of men, especially now men as young as 40 are being screened [for prostate cancer]," he added.
He said hospitals had a financial incentive to "churn" patients through the expensive da Vinci suites.
But Justin Peters, one of the leading surgeons using the da Vinci robot at the Epworth, said it would be "outrageous and completely untrue" to imply that he had any interest in promoting use of the robot other than for its benefit to patients.
He said that the new study did not take into account surgeons' levels of experience.
The study has been published in the Journal of the Amercian Medical Association.