In a speech to nearly 400 people at the Turkish consulate general in Hamburg, Cavusoglu criticized German authorities for favoring those opposed to the changes, which would introduce wide-ranging presidential powers.
“Those who are in favour of Yes in the referendum are obstructed, but but those who favour No are supported,” he said, referring to the April 16 vote on constitutional amendment.
“This not a right attitude. Nobody has the right to interfere in a referendum, in an election, in another country. This is also not democratic.”
Cavusoglu was speaking at the diplomatic mission after a planned address at a hall in Hamburg was cancelled on Monday. He said German police, intelligence agencies and local authorities had exerted pressure on the hall’s management to cancel the event on the grounds of insufficient fire safety.
“Unfortunately this is a systematic obstruction,” he said.
Since last week, there have been nine venue cancellations in six cities.
Cavusoglu accused German authorities of “double standards” and said he would raise the matter with Foreign Minister Sigmar Gabriel on Wednesday.
Nearly 3 million Turkish migrants live in Germany and around half are eligible to vote in the referendum. Turkish citizens in Germany can vote at diplomatic missions between March 27 and April 9.
The fallout over the referendum rallies is the latest sign of strained ties between Ankara and Berlin. Turkish politicians have criticized Germany and other western European nations for allegedly turning a blind eye to terrorist organizations such as the PKK and FETO.