Embattled oil refiner Petroplus yesterday said it will begin a temporary shutdown of three of its plants in January after lenders froze a $1 billion credit facility.

The Swiss firm will suspend operations at its Petit Couronne refinery in northern France, Cressier in the Swiss canton of Neuchatel and its Antwerp site in Belgium, according to a report in our sister publication, the Gulf Daily News.

The action followed Tuesday's announcement that banks had frozen about $1bn in uncommitted credit lines deemed "critical" to maintain its operations.

"The company will start temporary economic shutdowns of the Petit Couronne, Antwerp and Cressier refineries in January given limited credit availability and the economic climate in Europe," Petroplus said.

The firm, Europe's largest independent oil refiner, said it held meetings with lenders in Zurich on Thursday, describing the talks as "open and constructive." Further negotiations will take place in the coming days as the company seeks to get the credit restored.

"The restart of the refineries is dependent on economic conditions and credit availability," Petroplus said.

Petroplus Holdings AG is headquartered in the city of Zug near Zurich and headed by Frenchman Jean-Paul Vettier. The firm also owns the Coryton refinery in England and the Ingolstadt refinery in Germany, employing about 2,500 people across the five plants which have a combined capacity of about 667,000 barrels a day.

French workers had feared their plant would be hit by the credit freeze and appealed for government support following the announcement.

Ministers assured unions that they were pulling out all stops to assist Petroplus during its talks with lenders, understood to comprise 13 international banks. The spotlight fell on the Petit Couronne and Cressier sites as they were reportedly the least profitable in the last quarter.

Earlier this year Petroplus closed its Reichstett refinery in France which employed about 250 people. The credit freeze sent shares on the Swiss market tumbling and on Thursday credit ratings agencies Standard and Poor's and Moody's slashed the firm's rating, indicating it was vulnerable to default.

Yesterday, the Petroplus share price was up by about seven per cent to 1.76 Swiss francs after three days of falls which saw them lose more than half their value.