Malaysia's high court has reversed a policy banning Christians from using the word 'Allah' to refer to God. 

The ruling came after a lengthy legal battle involving a Christian woman, Jill Ireland Lawrence Bill, who had her religious materials seized at an airport because they contained the word "Allah". Following the 2008 incident, Bill filed a legal challenge against a 1986 ban on Christians using the word in their publications.

Finally, on Wednesday, the Kuala Lumpur High Court ruled that Bill should not be subject to discrimination on account of her faith.

The ruling also permits the use of three other words in Christian publications: 'Kaabah' (Islam’s holiest shrine in Mecca), 'Baitullah' (House of God), and 'solat' (prayer).

Justice Nor Bee said that the ban on the four words was "illegal and unconstitutional". 

"The freedom to profess and practise one's religion should include the right to own religious materials," she added.

A separate legal challenge was filed by a Catholic newspaper claiming that the government unfairly barred them from using "Allah" in their publications. The 2009 case resulted in a victory for the paper, but prompted outcry from the Islamic community and sparked a spike in religious tensions. A number of churches and a few Muslim prayer halls were attacked and even burned.

Then, in 2013, the decision was controversially overturned by the Court of Appeal, and the ban was reinstated. The term was banned in 1986 by the Malaysian Home Ministry, citing a threat to public order. 

But the judge insisted that the government had gone too far. "There is no such power to restrict religious freedom under Article 11. Religious freedom is absolutely protected even in times of threat to public order," she said. 

The laws surrounding the word have been a source of tension for years in the Muslim-majority country. Many of the Christian communities say that the law was blatantly discriminatory and insisted that they had been using the Arabic word to refer to God for centuries. Muslim leaders have suggested that allowing Christians to use the word "Allah" may lead to public unrest and confusion.

Roughly 13 per cent of the Malaysian population are Christian, while some 60 per cent are Muslim.