Pickets have been placed again by SIPTU members on a county Cork bio-pharmaceutical plant in a dispute over union recognition.

This is the fourth time in a month that there have been planned 33-hour work stoppages at the AbbVie plant at Carrigtwohill, in Co Cork.

A fifth stoppage is earmarked for next week.

SIPTU says the Labour Court ruled in favour of its members in relation to the dispute but that the company - which is listed on the New York Stock Exchange - is refusing to engage, or implement the Labour Court recommendation.

The global bio-pharmaceutical company employs 150 people at its east Cork site.

The company also has operations at Sligo and Dublin which are not affected by the dispute.

An spokesman for AbbVie had no comment to make when asked about the continuing industrial action.