Governments around the globe may have wasted billions of dollars stockpiling antiviral drugs to use against an influenza pandemic, according to a damning review drawing on previously suppressed data.

Australia was one of several countries to stockpile the drugs known as Tamiflu and Relenza, believing they would reduce hospital admissions and complications of influenza, such as pneumonia, in the event of an outbreak of swine or bird flu.

But a review of data from trials involving more than 24,000 people, published on Thursday by the Cochrane Collaboration and the British Medical Journal, concluded the drugs were of only marginal benefit, shortening the duration of influenza symptoms by just half a day.

The review found no good evidence that the drugs prevented the spread of the virus between people, or any of its serious consequences, such as infections. It found Tamiflu increased the risk of psychiatric disturbances, renal problems, nausea, vomiting and headaches.