An Iranian Christian prisoner has gone on hunger strike as authorities continue to refuse her essential medical care.

Maryam Naghash Zargaran, a friend and former colleague of Pastor Saeed Abedini, started a hunger strike on May 25 in protest against prison authorities refusing her access to essential treatment for long-standing health issues.

She has also refused to accept visitors to Evin prison where she is incarcerated.

Zargaran, known as Nisim, underwent heart surgery around nine years ago and needs frequent medical attention which is being denied because it would mean leaving the prison facility.

"Maryam hasn't left her bed in four days. She is burning with fever and has been on hunger strike to raise her protest against prison authorities' indifference toward her health, her request for temporary release or leave which every prisoner is entitled to," one of her family members told Mohabat News.

"She is suffering from serious health issues. Before going on hunger strike she had lost 25 KG and her health issues had intensified. Authorities do not show the slightest concern over Maryam's health. In addition, she is suffering from depression and takes depression medications for it," they added.

It's reported that her fellow prisoners have showed solidarity with Zargaran by forgoing family visits alongside her in a form of protest. 

Zargaran, 36, is a Christian convert from Islam who was arrested in early 2013 for her faith and charged with "action against national security". She was initially apprehended on 6 January 2013 and later transferred to Evin prison.

She was charged with "propagating against the Islamic regime and collusion intended to harm national security" and sentenced to four years in prison.

Abedeni took to Facebook in April this year to plea for the release of Zargaran, who was involved with Saeed Ministries.

"She was the first underground female leader and one of the five leaders who helped us start churches before I became a pastor," he said.

Abedini, also a convert from Islam, added: "Every time I got arrested, some leaders became afraid to work close to me and some left. But Nasim was the only one who stayed beside us until the end when I was put in Evin prison. This woman never gave up or chose fear and doubt. She always stayed beside us in Saeed Ministries until prison broke apart our ministry."