Thorbjorn Jagland, the Secretary General of the Council of Europe, said the tension between Turkey and several European countries was "damaging to diplomacy and democracy.
"We cannot allow it to escalate any further," Jagland said, adding that all Turkish citizens should have ample opportunity to be informed in the referendum campaign.
On Saturday, the Dutch government first canceled the Turkish foreign minister's flight permit to the Netherlands and then blocked a convoy carrying Turkey’s family minister from entering the Turkish consulate in Rotterdam.
Protests erupted outside consulate in Rotterdam, where Dutch police used guard dogs and baton to disperse peaceful crowd gathering in support of Family Minister Fatma Betul Sayan Kaya. She was later forced to leave consulate area with police escort.
"All public meetings and political campaigns held in Council of Europe member states should be conducted in accordance with national legislation and the European Convention on Human Rights." he said.
In a statement on Sunday, French Foreign minister Jean-Marc Ayrault said: "Faced with the current tension between Turkey and several member states of the European Union, France calls for appeasement."
"It also calls on the Turkish authorities to avoid excesses and provocations... In these circumstances, it is essential to be accountable and to avoid unnecessary polemics," the French minister added.
Azerbaijan Foreign Ministry Spokesman Hikmet Haciyev reacted to Netherlands' attitude towards Turkish ministers.
In a written statement, Haciyev described the Dutch treatment of Turkish ministers was "contradictory" and "prejudiced".
"What has been done against the Turkish government's officials, the hinderance of meeting and demonstration freedom of Turks in the Netherlands and the use of power against them is contradictory and prejudiced," Haciyev said.
Earlier, British Foreign Secretary Boris Johnson said the stand-off between Turkey and the Netherlands is “very regrettable” and should be sorted out “as fast as possible”.
Speaking at a weekend political program on ITV channel, Johnson said: "I think this is very regrettable. French Foreign minister Jean Marc Ayrault said the meeting of Turkish foreign minister in Metz " is a matter of freedom of assembly."
The Dutch government has canceled Foreign Minister Mevlut Cavusoglu's flight permit on grounds of "security" and "public safety".
The ministers were due to meet Turkish society ahead of April 16 referendum which will see a constitutional amendment.