Turkey on Saturday lashed out at "arrogant" German reaction to comments by President Recep Tayyip Erdogan urging ethnic Turks in Germany to vote against both parties in Chancellor Angela Merkel's ruling coalition.

The latest spat between Ankara and Berlin risks propelling a months-long crisis in ties between the two NATO allies to a new level ahead of Germany's September 24 general election.

Erdogan said ethnic Turks in the country should not cast their ballots for Merkel's Christian Democratic Union (CDU), the Social Democratic Party (SPD) of Foreign Minister Sigmar Gabriel or the Greens, labelling all three parties "enemies of Turkey".

Gabriel condemned Erdogan's comments as an "unprecedented act of interference" while Merkel's spokesman Steffen Seibert said on Twitter: "We expect foreign governments to not interfere in our internal affairs."

The SPD's chancellor candidate Martin Schulz went even further, saying Erdogan had "lost all sense of proportion".

But Turkish Deputy Prime Minister Bekir Bozdag, who is also the official government spokesman, strongly defended Erdogan's comments saying they were only aimed at Turkish-origin voters in Germany.

"This was expressed very openly and clearly. But then look at these very disrespectful and very arrogant reactions that go beyond the bounds of decency," he said in televised comments.

"I want to condemn these reactions and the disrespectful language used," he added.

Bozdag accused Germany of meddling in Turkey's April 16 referendum on expanding Erdogan's powers saying the German "government's attitude was very clear" in backing the 'No' camp.

He also reaffirmed past Turkish accusations against Germany that it was giving refuge both to wanted Kurdistan Workers Party (PKK) militants and suspected plotters in the July 15, 2016, failed coup bid.

"Germany supports the PKK," said Bozdag. "The PKK is a terror group but Germany quite clearly gives it protection."

Analysts say that some 1.2 million people of Turkish origin will have the right to vote in the September polls as German citizens.

Source: AFP