That further delays OMV's entry into the Russian company's Achimov IV and V phase development in the Urengoy gas fields. The two groups had agreed in 2016, to swap 38.5 percent of OMV's Norwegian assets for 24.98 percent of the Russian assets.

However, they gave in to opposition from Norway in October, cancelling the swap deal and saying OMV would buy the assets.

"We will do everything we can to finalise this in the summer," Rainer Seele said on Sunday.

In recent months, OMV has shifted its focus more towards the Middle East. It announced a landmark partnership deal with Abu Dhabi's National Oil Company (ADNOC) and Italy's Eni on Sunday.