Following the outbreak of swine flu, Swiss drug maker Roche Holding AG said Wednesday it was working closely with the World Health Organization to make its Tamiflu drug available to patients.

The drug company said it had increased its level of preparedness after the alert level was raised by the WHO. While Denmark's head of disease prevention said on Wednesday the country had an existing stockpile of Tamiflu tablets to which they intended to add supplies of GlaxoSmithKline's inhaled antiviral Relenza.

Originally invented by U.S. biotech company Gilead Sciences Inc, Tamiflu, or oseltamivir, is given as a convenient tablet and both Tamiflu and Relenza work against the H1N1 strain of swine flu now circulating across many countries.

However, the reason Denmark is adding Relenza to its stockpiles of Tamiflu is as there have been widespread reports of seasonal H1N1 flu becoming resistant to Tamiflu. The earlier fears of bird flu had resulted in many countries building stockpiles of Tamiflu and some Relenza.

Else Smith, Director of the National Centre of Health Promotion and Disease Prevention, said stockpiling Relenza was a precaution as there was no guarantee that swine flu would respond to Tamiflu in the months ahead, she added that the minister had agreed to go ahead and buy the medicine.

"The national board of health has recommended to the minister of health that it buys 40,000 treatments of the drug Relenza," she told a news briefing. 

Roche said packs in a "rapid response" stockpile that can be deployed at the request of the WHO it had donated 5 million packs of Tamiflu to the WHO, including 3 million earlier. The company said they had also fulfilled government pandemic orders amounting to 220 million treatment courses.

A spokeswoman for Roche said governments had been in touch with them regarding new orders since the swine flu outbreak but did not quantify. The company said they were increasing production of Tamiflu but warned that the time required was eight months for the drug from synthesis of the product to packaging.