March 27 (Reuters) - Ithaca Energy has received a four-week exclusivity period from Italy's biggest energy company Eni to make a potential offer for its UK upstream assets, the North Sea oil and gas producer said on Wednesday.

The company said it will buy Eni UK in exchange for its own shares and Eni will become a major shareholder by holding between 38% and 39% of the enlarged issued share capital.

A potential offer for Eni's UK assets includes its recently acquired Neptune Energy assets, but excludes its carbon capture, utilisation and storage (CCUS) and Irish sea assets, Ithaca said in a statement. (Reporting by Eva Mathews in Bengaluru; Editing by Savio D'Souza and Subhranshu Sahu)