Tamiflu maker Roche today posted a 29% dive in profits despite desperate demand for the swine flu drug.

But the Swiss drugs giant expects stronger earnings over the next 18 months as swine flu spreads.

Production of Tamiflu, the anti-viral treatment for those with swine flu, is on course to hit 400 million packs annually by the end of the year.

Governments around the world are ordering Tamiflu and other treatments to deal with the swine flu outbreak.

The UK is the worst-hit country in Europe. Roche said it now expects “double-digit” sales growth this year and next, having earlier forecast “mid-single-digit” growth.

First-half profits fell to Swfr4.1 billion (£2.3 billion) from Swfr5.7 billion a year earlier after it was hit by financing costs related to its takeover of Genentech.

Analysts were looking for profits of Swfr5 billion. Group sales were up 9% to Swfr24 billion. Roche sealed its acquisition of San Francisco-based Genentech in March, having held a stake for almost 20 years.