Radical religious groups in Pakistan have threatened the lives of Supreme Court judges and called for mass protests ahead of the publication of their decision in the Asia Bibi case.

The case of the Christian woman sentenced to death by hanging for blasphemy has focused world attention on Pakistan's harsh religion law. First arrested in June 2009 after an altercation with Muslim workers, she has appealed repeatedly without success. The Supreme Court heard her final appeal on Monday, but said it would 'reserve judgment'.

According to World Watch Monitor, hardline Islamist party, the Tehreek-e-Labaik Pakistan (TLP), threatened the judges in a press conference on YouTube, saying that if she were to receive clemency, the justices would meet a 'horrible' end.

Meanwhile another religious group, the Red Mosque in Islamabad, asked the Supreme Court to order that, if Asia Bibi is released, she would not be able to leave the country.

'Western forces are trying to get Asia Bibi out of the country but she should be hanged,' the petitioner, Hafiz Ihtesham Ahmed, told AFP.

The TLP also announced it would hold a rally today, October 12. On social media radical voices call for Asia Bibi to be hanged.

The blasphemy law in Pakistan is widely abused and used to settle private and inter-communal scores. It is hard to secure acquittals and defendants are often attacked or lynched.

Blasphemy cases have risen sharply in recent decades. World Watch Monitor says at least 150 Christians, 564 Muslims, 459 Ahmadis and 21 Hindus have been jailed under blasphemy charges since 1986.

In 2011 two prominent Pakistani politicians, Salmaan Taseer and Shahbaz Bhatti, were assassinated after they spoke publicly in Asia Bibi's defence.

No judicial execution for blasphemy has so far been carried out in Pakistan.