The closure of the Liebert plant in Cork with the loss of 150 jobs, announced yesterday, brings the toll on jobs in the city and county in the past month to 800.

Liebert - which makes air cooling systems for computers - yesterday announced it was closing its Cork plant at the end of June as part of a rationalisation programme following the purchase of its rival, the Hiross group, last year.

According to Liebert, the product portfolios of both companies had been reviewed and certain products would be discontinued. "This leaves Liebert Europe with excess manufacturing capacity and the hence the decision to close the Cork plant," it said.

The losses follow Monday's announcement that Bourns Electronics is to lay off 120 staff at its plant in Mahon and the news last month that Apple Computers was transferring production of its iMac to Wales with the loss of 450 jobs.

Liebert, which was established in Cork in 1983 and employed 225 people at its peak, said that although a number of technical positions would become available at its Italian and Slovakian plants, all other employees would become redundant.

SIPTU branch secretary Mr Harry Carroll said news of the closure came at a 10-minute meeting with staff which was addressed by managing director, Mr Brendan Costelloe and a senior manager from Liebert's parent company in the US.

"The workers were utterly and totally shocked by the news. While we were aware the company had acquired a new company in Europe, we had been consistently and repeatedly informed by management that this acquisition would not impact negatively on the plant in Cork," he said.

"This company was on its knees three years ago and as a result of my members out there and, indeed local management, the company exceeded its sales targets last year by more than 25 per cent. They are highly profitable and they have a very healthy order book."

The Tanaiste, Ms Harney said she regretted the latest job losses.