The number of men diagnosed with prostate cancer in Australia has increased 276 percent during the last two decades, a study by leading cancer organization Cancer Council NSW (New South Wales) revealed on Thursday.

Associate Professor Freddy Sitas, lead researcher from Cancer Council NSW, said the rise in new cases was likely due to increased prostate specific antigen (PSA) blood tests and digital rectal exams being used to identify men with prostate cancer.

"At the moment we are working with imperfect tests," he said in a report.

"The current tests often fail to distinguish between a low-risk prostate cancer from one that is life threatening."

Sitas said the tests have saved men with aggressive forms of the disease but at a high cost.

"The increased number of men diagnosed has led to many having highly invasive treatments resulting in unnecessary long-term health complications," he noted.

"This is why the governments in Australia do not support a PSA- based population screening program."

The study also found the increase in new cases was much greater than the 27 percent drop in prostate cancer deaths over the past 20 years from 1987 to 2007.

"This reflects the inaccuracy of the screening tests and indicates that many men were diagnosed with cancers that would not have harmed them," Sitas said.

"Saving lives is our priority, but we urgently need a better test so that we can achieve much better mortality outcomes without so many men being diagnosed with indolent cancers that would not have harmed them."

Professor Mark Harris from the University of New South Wales said men need to be fully informed about the pros and cons of testing as the current test falsely identifies many men without cancer.

"Men who do have a concern should have a good and thorough talk to their doctors about the implications," he said.

"The patient needs to decide if it is the most appropriate thing for them."