He called the decision "bad news for everyone in Europe".
In his opinion, if Nord Stream 2 is launched, gas transit through Ukraine will be stopped.
“Ukraine will face the specter of freezing to death in winter,” the Prime agency quoted him as saying.
Wozniak added that in this case, Kyiv would have to turn to Moscow "for inclusion in the Russian gas system."
He believes this "will of course have political implications".
Earlier, the European Court of Justice partially upheld the suit of Nord Stream 2 AG against the European Commission on amendments to the EU Gas Directive.
In November, the German regulator suspended the certification of Nord Stream 2 AG as an independent operator of the Nord Stream 2 pipeline.