Ahmet Turk, the co-chairman of the Democratic Society Party (DTP), called on Kurdish people to stay away from violence.
He said in an interview with CNN-Turk television on Sunday that "violence causes only more violence".
Several DTP officials have been accused of fanning the unrest in the mainly Kurdish southeast, where youths set government buildings and banks on fire, vandalised shops and attacked the police with petrol bombs and stones.
Eight people died in the disturbances.
Turk admitted that his party did not have full control over the local population as many remained under the influence of the outlawed separatist Kurdistan Workers' Party (PKK), which has been encouraging the violence.
He said the riots, which erupted on Tuesday in Diyarbakir after the funerals of PKK rebels killed while fighting the army, were the reflection of political, social and economic problems that have plagued the southeast, Turkey's most underdeveloped region, for decades.
"Those people do not have education, health services ... they are hungry and deprived. How can one control such masses?" he said.
Turk called on the government to come up with a comprehensive programme for the region that would include the improvement of Kurdish cultural and political rights, economic and social development and a general amnesty for the PKK.
"How can you resolve the problem only with the stick, with repression and silencing? We want this mentality to change," he said.
"The [Kurdish] people believe they are still regarded as a kind of quasi-citizen"
Ahmet Turk, the co-chairman of the Democratic Society Party
"The [Kurdish] people believe they are still regarded as a kind of quasi-citizen."
Fighting between the PKK and the army since 1984 has claimed nearly 37,000 lives, ravaged the meagre infrastructure and the mainstays of farming in the southeast, and prompted huge numbers of peasants to migrate into urban slum areas.
The region had been relatively calm in recent years as the PKK declared a unilateral ceasefire in 1999 and Ankara, under European Union pressure, granted the Kurds a measure of cultural rights, lifted emergency rule in the region and began compensating villagers who had suffered in the conflict.
Tensions have been on the rise, however, since June 2004, when the PKK, blacklisted as a terrorist group by Turkey, the EU and the United States, called off the five-year truce.