Representatives of several Egyptian parties, movements and unions marched at the funeral of late leftist activist and rights lawyer Sayed Fathi, who passed away suddenly on Tuesday.

The funeral march was held in front of the Egyptian Journalists Syndicate in downtown Cairo on Wednesday afternoon.

Fathi's body was later buried in his hometown of Bahteem in Giza.

Fathi suffered a heart attack after leaving court, where he had been attending a hearing in the case of activist Ahmed Duma, who remains detained on charges of 'insulting' Egyptian President Mohamed Morsi.

Fathi, a graduate of Cairo University's law faculty, was the founder and head of the Helali Legal Rights Organisation, which provides legal services for political prisoners and labourers.

Shortly before Egypt's 25 January 2011 uprising, Fathi co-founded the Front for Defending Egyptian Protesters, sending lawyers to advocate for arrested demonstrators.

Fathi represented the families of slain protesters in the case against ousted president Hosni Mubarak, who has been accused of complicity in killing hundreds of unarmed anti-regime demonstrators.

"Fathi played a prominent role defending the rights and freedoms of the Egyptian people," read a statement by the Socialist Popular Alliance Party in tribute to the deceased lawyer.

"Throughout his journey, he defended wronged workers and prisoners of opinion – a wonderful journey, which he concluded while still defending the martyrs and detainees of the revolution through the era of the [Muslim] Brotherhood," the party added.

Fathi leaves behind a wife – activist and rights lawyer Abeer Isaac – and one daughter.