Manufacturing production decreased by 2.1 per cent in November compared to the previous month, according to figures published yesterday.

Following an unusually sharp fall in September, driven by the pharmaceutical sector, total industrial production remained depressed in the final months of the year.

According to data released by the Central Statistics Office, seasonally adjusted output for manufacturing industries was 14.4 per cent lower in the three months to November 2012 than in the preceding three-month period.

Although industrial production in Ireland tends to be highly volatile, levels of output in the three months to November were at their lowest since 2009.

Production in high-tech and chemical industries in November, known as the “modern sector”, declined by 2.5 per cent on the month. Partially offsetting this decline was a monthly increase of 1.9 per cent in “traditional” sectors.

Detailed sectoral data of the September-November period provides the strongest evidence yet that the expiration a year ago of patents on some medicines made in Ireland is having a major impact on the pharmaceutical industry.

The monthly decline in output in the pharmaceutical sector in September, at 37 per cent, was the third highest such fall since the mid-1990s, when the sector began to grow rapidly.

Of greatest concern is that, in contrast to the other two larger declines, there was no sharp rebound in the sector subsequently.

In the September-November period output in the sector was back at 2009 levels, reversing the very strong growth that had been registered since that time.