Former trade union leader Lutf Amim Shibli who went on a hunger strike to protest against Gen Raheel Sharif's retirement from the position of army chief died in Karachi on Wednesday, SSP South Saqib Ismail Memon said.

Memon said 66-year-old Shibli started his protest on November 1 by camping outside the Karachi Press Club and going on a hunger strike.

"Shibli suffered from diabetes and high blood pressure...he was taken to Jinnah Hospital on November 27...he passed away on Wednesday, Nov 30," the SSP said.

Head of emergency at Jinnah hospital, Dr Seemin Jamali, said Shibli had no pulse when he was brought to the hospital but the doctors had managed to resuscitate him.

She added that once his condition was moderately stable, his family members were told that they could move him to Aga Khan University Hospital.

Shibli was taken to Aga Khan where he passed away, SSP South said.

Media reports have also raised questions about Shibli administering poison on himself and committing suicide but these could not be verified and the family did not allow a post-mortem.

Deputy general secretary of the National Trade Union Federation (NTUF), Nasir Mansoor, said the NTUF believed that Shibli's death was a tragic event "even though we did not agree with his method of protest... the Union believes in a life of struggle."

Shibli had once served as chairman of the Progressive Workers Union at the Karachi Port Trust (KPT), Mansoor added.

Union sources said Shibli's funeral prayers will be held at 2:50pm today in front of the KPC as per the deceased's will.