BASEL, Switzerland - Swiss pharmaceuticals company Roche Holding AG said Tuesday it is donating 5.65 million packets of Tamiflu, one of two anti-viral drugs known to be effective against swine flu, to the World Health Organization.

Roche said 5 million packets will be used to replenish stockpiles that were depleted when WHO sent previously donated supplies to poor countries after the appearance of a new type of swine flu, dubbed H1N1. A further 650,000 packets containing smaller doses of the drug will be used to create a new stockpile for children.

Each packet of the drug is enough for one course of treatment.

"The recent outbreak of influenza A (H1N1) shows that such a virus can be totally unexpected and spread rapidly around the globe," the head of Roche's pharmaceuticals division, William M. Burns, said.

"This emphasizes the urgency of restoring WHO and Roche Rapid Response Stockpiles, alongside national government stockpiles, to prepare for subsequent waves with this virus or for addressing newly emerging influenza strains."

Roche said it can make 110 million packets over the next five months -- or about 22 million a month -- and increase production capacity to 36 million a month by the end of the year if there is sufficient demand.

"This equates to a maximum annual capacity of 400 million treatment courses per year," the company said.

But with WHO estimating that up to 2 billion people could become infected with the disease over the next two years, some experts have questioned whether Roche should be allowed to dictate the production of Tamiflu in the event of a pandemic.

The Basel-based company has licensed the drug to several other producers to make a generic version -- known as oseltamivir -- but there is no guarantee they and Roche would be able to produce enough doses if the virus spreads rapidly.