Yusef Nadarkhani, an Iranian pastor facing the death sentence for converting from Islam to Christianity might be liberated after his lawyer told AFP on Thursday he is "optimistic" that the final verdict could see his client set free.

"Our last court session was held on Wednesday. Mr Nadarkhani did not repent and the last court verdict said he would face a death sentence if he did not," Mohammad Ali Dadkhah said.

"However, we offered our explanations and I think the court was convinced. I am optimistic there is a 95 per cent chance he will be released in the final ruling, which I expect by the end of next week," Dadkhah added.

Nadarkhani, now 32, converted from Islam to Christianity when he was 19 and became pastor for a small Protestant evangelical community called the Church of Iran and reportedly held services in underground "home churches" in Rasht, a provincial town about 240km north-west of Tehran.

In 2009, he challenged the regime's insistence that all schools should teach Islam, which led to him being put on custody and later charged.

Nadarkhani was arrested in October 2009 and condemned to death for apostasy as the country still operates under the strict Islamic sharia law, which also states that for such verdicts to be overturned, the convicted person needs to 'repent' and convert back to Islam.

Following Nadarkhani's refusal to reverse to Islam, an appeal court in Gilan maintained his conviction in September 2010, forcing the pastor to turn to the Supreme Court.

His wife, had also been arrested and sentenced to life imprisonment, but was later on released on appeal.

In July it was reported that Iran's Supreme Court had overturned the death sentence, sending the case back to a court in his Nadarkhani's hometown of Rasht.

The case provoked international outrage and was criticised by various western countries.

British Foreign Secretary William Hague said he "deplored" reports that Iran was about to execute the pastor for refusing to return to Islam and U.S. House Speaker John Boehner had urged Iran to spare Nadarkhani's life and grant him "unconditional release."

Nadarkhani's Lawyer Dadkhah had also suffered Iran's strict legal regime as he was sentenced to nine years in jail and a 10-year ban on practising law or teaching at university for "actions and propaganda against the Islamic regime" by a Teheran court.

The lawyer said he had been targeted after he cooperated with the Centre for the Defence of Human Rights, an organisation founded by Nobel peace laureate Shirin Ebadi, as well as for giving interviews and pleading for his client's case on foreign radio stations.

He has appealed his case and is awaiting a verdict.