Turkey's Barcelona player Arda Turan on Friday angrily hit back at critics who slammed the midfield star for joining a campaign backing greater powers for Turkish President Recep Tayyip Erdogan.

Turan, for long an impassioned supporter of Erdogan, had been vilified on social media after posting a video on Wednesday supporting the presidential system plan.

Turkey is heading to a referendum in April on the changes to the constitution -- seen as a crossroads in its modern history -- after the changes were backed by parliament.

"Expressing one's opinion is one of the fundamental and necessary conditions of democracy," Turan wrote in a lengthy and emotional posting on his hugely popular Instagram page.

The player complained he had been targeted with accusations that he did not love his home country or its modern secular founder Mustafa Kemal Ataturk.

"No-one has the right to question my love for my country and Ataturk with unfounded accusations," Turan said, adding he sought to apply Ataturk's principles "every moment of my life".

"I can tolerate every kind of criticism but I cannot tolerate insults about my love for the fatherland and love for the flag."

"This country is my love. I want to emphasise this again."

Turan and his fellow former Galatasaray star Burak Yilmaz, who now plays for Beijing Guoan, joined a social media video campaign started by Turkish football legend Ridvan Dilmen for voters to back a 'Yes' vote in the referendum.

In the second video in the chain, Arda responded: "I have heeded the call from Ridvan. I am also in for a strong Turkey. Burak Yilmaz, my brother, are you also in?"

Actor Baris Atay, a known longtime critic of Erdogan, issued a counter video with the message "we are against one-man rule and dictatorship".

Arda Turan, who was raised in the low income Istanbul district of Bayrampasa, has been a vocal supporter of Erdogan throughout his rule as premier from 2003-2014 and then president.

Erdogan won thumping support from Turan in the wake of the failed July 15 coup aimed at ousting him from power, with the football superstar appearing at rallies in his support.