The pipelines, which transport Russian gas to Germany via the Baltic Sea, have been opposed by the Polish government, which has said they increase Europe's dependency on Russian energy.
Arguments over the pipelines opened up rifts in the EU between its eastern and western members.
"The European Union will never be a conflict-free zone," said Thomas Bagger. "It is rather a method of peacefully balancing the interests of its members, it is a kind of institutionalised dispute that takes place according to established rules.
"It does not mean that all decisions made in this way are right and I am the last person who would say that the Germans always make the right decisions. Nord Stream II, but also Nord Stream I were a mistake."
When asked which government made these decisions that led to the "mistake" he replied: "Different German federal governments, one after another. Yes, Angela Merkel's government too."
In September last year the two pipelines developed multiple ruptures, resulting from suspected sabotage. (PAP)