"For Tamiflu, the key need today is the rapid expansion of production capacity," said William Burns, head of the Basel-based firm's drug division. "In addition, we are prepared to discuss all available options, including granting sub-licenses, with any government or private company who approach us to manufacture Tamiflu or collaborate with us in its manufacturing."

Roche has ruled out relinquishing its patent on Tamiflu, which runs to 2016.

Roche is reportedly donating 20,000 packs of Tamiflu to Turkey, to protect workers who might come into contact with infected poultry, and has also given three million packs to the World Health Organization. Contact with infected poultry is currently the predominant form of transmission of the H5N1 virus.

Tamiflu, known generically as oseltamivir, is the most effective anti-viral drug currently available for H5N1 avian flu.

Currently, human-to-human transmission of the avian flu has not been verified. Thus, no pandemic. The flu virus must first mutate to allow human-to-human transmission for avian flu to become a widespread danger. Those mutations that would make a human pandemic possible may also render Tamiflu ineffective.