Eni was owed $3.3 billion by Venezuela's oil company PDVSA at the end of last year, including around $1 billion in accrued interest, the Italian company said in its annual report on Tuesday.
Eni and Spanish oil company Repsol produce gas at their jointly owned Perla offshore field - the only active offshore gas project in Venezuela - with output purchased by PDVSA mainly for domestic power generation.
The Venezuelan group has defaulted on its payments for those gas volumes and accumulated debt to Eni and Repsol, which were unable to receive in-kind payments from PDVSA due to the tightening of US sanctions.
Sanctions cut PDVSA off from the international financial system and prevented it from using dollars for commercial transactions.
The situation has improved, however, since the start of this year, Eni said, after Venezuela approved a partial reform of its hydrocarbons law and Washington eased sanctions, allowing certain energy companies to operate there.
Those recent developments could increase the likelihood of recovering its claims against PDVSA, Eni added.
Eni also said it has been in contact with US authorities about its potential involvement in a relaunch of Venezuela's oil sector.
Repsol said last month that it was owed 4.55 billion euros by Venezuela.
(Reporting by Francesca Landini; Editing by Cristina Carlevaro and Joe Bavier)
