WARSAW, March 2 (Reuters) - Ukrainian state energy company Naftogaz is seeking to join Polish gas firm PGNiG in a court case challenging the European Union's decision to give Russia's Gazprom more access to the Opal gas pipeline in Germany.
Naftogaz said on Thursday it had asked permission from the European Court of Justice (ECJ) to intervene in the case initiated by state-controlled PGNiG at the end of last year.
In October, the Commission decided to lift a cap on Gazprom's use of Opal, which carries gas from the Nord Stream pipeline under the Baltic Sea to customers in Germany and the Czech Republic.
Poland, which imports most of the gas it consumes from Russia, said the decision threatened gas supplies to central and eastern Europe and would strengthen Gazprom's dominant position in the region.
"Joining the case initiated by PGNiG will enable Naftogaz to present additional arguments and gain access to the case files. The request by Naftogaz is now awaiting consideration in the court," Naftogaz said in a statement.
It also said the Commission's decision could threaten the stability of gas supplies to Ukraine because of possible interruption of gas flows from Poland.
The ECJ has already suspended the Commission's decision on Opal.
In December, Ukrainian President Petro Poroshenko said Ukraine and Poland would act jointly to block projects that could result in Gazprom gaining greater access to the European gas market by bypassing Ukraine. (Reporting by Agnieszka Barteczko; Editing by Lidia Kelly and Mark Potter)