Veteran politician Sardar Sherbaz Khan Mazari passed away on Saturday at the age of 90, his family said in a statement.
"The Mazari family is deeply grieved to announce the passing away of our cherished elder, Sardar Sherbaz Khan Mazari," it said.
"A devoted and loving patriarch, fiercely dedicated to his country, loyal to his friends — he commanded respect for his unwavering integrity. He was much revered by his tribe, where his sense of justice prevailed in resolving conflict through tribal faislas (decisions)," the statement added.
Offering his condolences, activist and lawyer Jibran Nasir called Mazari a political leader of "rare integrity with many contributions towards initiating the democratic process in Pakistan".
Mazari, a tribal chief from Rojhan Mazari — located in Punjab, close to the Balochistan border — was founder of the National Democratic Party (NDP). In the 1970 elections, which resulted in the separation of East Pakistan, Mazari had contested as an independent candidate and was elected as a member of the National Assembly.
He was among those who opposed military action in East Pakistan.
Mazari was as a vocal opposition member in the National Assembly from 1975 to 1977. He had played an important role in the preparation of the 1973 Constitution and later during the Movement for the Restoration of Democracy.
In recent years, he was no longer active in politics due to old age and indisposition.
Mazari was also the brother-in-law of late Baloch nationalist leader and chief of the Jamhoori Watan Party Nawab Akbar Bugti.
He will be laid to rest at his ancestral graveyard in Rojhan, according to the statement.