Irish-based oil and gas explorer Petroceltic is set to begin drilling and testing in the Tunisian field it believes holds 400 million barrels of oil within days.

The company recently raised $29 million (€23.5 million) through placing shares with institutional investors, to finance this and several other projects.

In a statement, Petroceltic said that it was shipping the necessary equipment to the site of its well at Sidi Toui, Ksar Hadada in southern Tunisia. It predicted that drilling and testing would begin within days.

The well is next to a site where drilling uncovered large quantities of oil in the 1950s. Petroceltic and its advisers believe that Sidi Toui could contain up to 400 million barrels of oil. The company owns 95 per cent of the field.

Petroceltic's chief executive, Mr John Craven, said yesterday that the high price of oil and gas meant there was a renewed focus on discovering and developing new deposits.

The company also has interests in the Celtic Sea, close to proven natural gas desposits. Recently it acquired prospects in Algeria and Italy.