Sources close to Christian Solidarity Worldwide (CSW) say there has been no major improvement in the condition of His Holiness Abune Antonios and he is being subjected to daily humiliation.
He was illegally removed from his office in January 2006 after repeatedly resisting interference by the Eritrean government in church matters.
It is alleged His Holiness Abune Antonios' movements are currently restricted by officials to two rooms within the servants quarters of a villa belonging to two junior bishops.
Elizabeth Chyrum, Director of Human Rights Concern-Eritrea (HRC-E) said: "It is an insult that the legitimate patriarch of the Orthodox Church is confined to the servants' quarters in the same compound where two junior bishops live in a villa.
"This was clearly and deliberately done to subject him to daily humiliation."
There was speculation in July this year that the Orthodox leader might be imminently released and reinstated after he made a public appearance in church.
Hopes were dashed after His Holiness Abune Antonios was stopped from asking a question during the service and promptly whisked away from the building afterwards.
Meryn Thomas, Chief Executive at CSW - a charity which advocates for persecuted Christians - said: "We reiterate our call for the patriarch's unconditional release and reinstatement and for representatives of sisterly Oriental Orthodox churches to visit him, not only to ensure his reinstatement and wellbeing, but also to verify the reconciliation process that is alleged to have occurred between the patriarch and renegade clergy."