The diplomatic row erupted after Angela Merkel’s Defence Minister Ursula von der Leyen called on people to support the “healthy, democratic resistance of the young generation” in Poland.
Mrs von der Leyen’s comments sparked outrage in Warsaw where she was accused of “interfering” in Polish politics.
Relations between Poland and Germany have nosedived over the last year with claims for Second World War compensation payments only adding to existing tensions surrounding controversial judicial reforms in Warsaw and increasingly nationalist rhetoric from the ruling conservative Law and Justice (PiS) party.
Polish Foreign Minister Witold Waszczykowski said Mrs von der Leyen’s statement was a case of explicitly “admitting that the German side is interfering in political life in Poland”.
Mr Waszczykowski said: “For the last two years we have been hearing from German politicians that they are neutral and that whatever is being said in the German media is just independent publications that the German authorities have no influence on.
“We hope it’s just a slip of the tongue that can happen to a politician.”
Poland’s defence ministry described the remarks as unacceptable and ordered its Department of Military Foreign Affairs to summon the German Defence Attaché for explanations.
Anna Pęzioł-Wójtowicz, a spokeswoman for Poland’s defence ministry, said: “The Ministry of Defence considers it unacceptable for the minister of a country that is a member state of the North Atlantic Alliance to call on citizens of another country to undertake anti-government activities.”
A spokeswoman for the German embassy in Warsaw said Mrs von der Leyen’s remarks had been mostly positive but part of them had been taken out of context.
Mrs von der Leyen was speaking to German broadcaster ZDF when she said her children had been studying in Poland as part of the European Union’s Erasmus student exchange programme at a time when there was a power shift in Warsaw.
She told ZDF it was important to support the “healthy, democratic resistance of the young generation” in Poland.
She said: “Our task is to maintain the discourse, to argue with Poland and Hungary.”