A 65-year-old Christian convert in Iran has been imprisoned on charges of "acting against national security" and alleged "propaganda against the system".

Mahrokh Kanbari was sentenced to a year in prison after appearing in the Islamic Revolutionary Court in Karaj, reports aid group International Christian Response. 

Kanbari was arrested by Iranian intelligence agents at her home on Christmas Eve last year.  The aid group reports that at this time, her Bible and other Christian items were confiscated from her.

She was released on bail but in January this year, she was charged with acting against the country's national security and told to see a religious leader in order to return to the Muslim faith.  

Kanbari is the latest in a long line of Christians to be imprisoned for her faith in Iran. 

The Muslim-majority country ranks ninth on the Open Doors World Watch List for the persecution of Christians and has a long history of arresting church members and pastors. 

"Spreading propaganda against the regime" is a common charge. In May, the Iranian courts upheld the prison sentences of Christian converts Saheb Fadaie and Fatemeh Bakhteri, who were both found guilty of this charge.

Fadaie was sentenced to 18 months in prison and given two years in internal exile in Nehbandan, a remote area close to the border with Afghanistan, while Bakhteri was sentenced to 12 months. 

They were both involved in house churches.  In delivering the sentences last September, the court equated discussions of Christian doctrine in house churches to an attack on Islam, according to Christian Solidarity Worldwide (CSW).

After their appeals were dismissed, CSW chief executive Mervyn Thomas said the sentences were "illustrative of the heightened campaign of repression that has seen Christians receiving excessive charges and sentences merely for manifesting their religion in private and in community with others".

"Many more are being punished for adopting a religion of their choice, which is protected under Article 18 of the International Covenant on Civil and Political Rights, to which Iran is party," he said.

"Moreover, the effective designation of Christian doctrine as an attack on Islam amounts to the criminalisation of the Christian faith."