MILAN (Reuters) - Eni executive Roberto Casula, who is being investigated over corruption allegations, has taken a leave of absence from the Italian oil major.

Casula, a former head of Africa operations for the state-controlled major, has been questioned by Milan prosecutors in a case involving alleged corruption in the Congo Republic.

"Noting the recent allegations made against me, and given the esteem in which I hold our business and colleagues, I have decided to take a temporary leave of absence from work," Casula said in an emailed comment to Reuters.

"My primary objective is to fully and promptly address these allegations and cooperate to the fullest extent with the judicial authorities."

Casula is also one of a series of defendants, including the Eni CEO, due to stand trial next month over alleged corruption in Nigeria in a case involving the 2011 purchase by Eni and Shell of the OPL-245 offshore oilfield.

The companies and Eni's CEO have denied any wrongdoing.

"Eni hopes for Mr Casula's swift return to work. In the meantime (his) position... has been temporarily covered by another senior manager," an Eni spokesman said.

Casula is Eni's chief development operations and technology officer. His position is being temporarily filled by Alessandro Puliti, who is executive vice president of reservoir and development projects, Eni said on its web page.

(Reporting by Stephen Jewkes in Milan and Libby George in London; Editing by Mark Heinrich and Adrian Croft)