U.S. healthcare group Johnson & Johnson made a long-awaited 1.75 billion euro ($2.3 billion) bid for Crucell on Wednesday, shrugging off the Dutch biotech company's recent problems with vaccine production.

The acquisition would catapult J&J, which already owns 17.9 percent of Crucell, into the global vaccine market given the biotech firm's strong position in vaccines for childhood diseases and its focus on developing influenza vaccines.

J&J had revealed in September it was in talks to buy the outstanding shares in Crucell but quickly ran into opposition from certain key investors who believed it was worth more.

The large pharma companies need new products, and J&J and Crucell have been working together for years so they know each other, it is a good fit, said Tom Muller, analyst at Theodoor Gilissen.

Short term it's the childhood vaccines, but over the next five to six years it's the influenza vaccine, that will generate huge growth for J&J given the worldwide demand for influenza vaccines, Muller added.

In October, Crucell said sterile operations at a South Korean plant might have been compromised and that its 2010 financial outlook, for revenue and other operational income to exceed 2009 levels, no longer held.

Crucell shares had fallen after this setback. But on Wednesday the stock was up 1.1 percent at 24.03 euros per share after the announcement of J&J's recommended cash offer of 24.75 euros per share.

J&J said the offer was subject to fulfillment of certain conditions including a minimum acceptance level of at least 95 percent of the shares, which will be reduced to 80 percent if certain conditions are met.

It will accept shares from Thursday until February 16.

(Additional reporting by Sara Webb)