INA is investing more than 4 billion kuna ($521 million/532 million) to upgrade the Rijeka oil refinery, the largest and most expensive industrial project in the Croatian history, the company said in an emailed statement to SeeNews.
Production operations need to be temporarily halted in order to connect the refinery's existing facilities to newly constructed systems and for that reason a number of suspensions have been planned for the period of upgrade works, with the next one to come in November.
INA will do everything possible to ensure uninterrupted supply to the domestic market in this period, it added.
The upgrade of the refinery started in 2020.
Hungarian energy company MOL holds a 49.08% stake in INA, while the Croatian government owns 44.84%.
INA's shares last traded on October 18 on the Zagreb Stock Exchange, closing 1.74% higher at 3,500 kuna.
($=7.531 kuna)