The Islamic State has hijacked a Sydney church website and replaced its homepage with a graphic video and threatening message.

The video relayed footage of gruesome deaths of Islamic State victims who have been beheaded, shot and even burned alive in the Middle East.

‘Hacked by Islamic State,’ text on the black homepage read on the Our Lady of Mercy Syriac Catholic Church website, based in Concord in Sydney’s west.

The Our Lady of Mercy Syriac Catholic Church website, based in Concord in Sydney’s west, was hijacked by a group claiming to be the Islamic State on Thursday

‘We don’t negotiate except with cannon, we don’t have dialogues except with guns,’ the text said.

Parish priest Rahal Dergham told Daily Mail Australia that their church community is mostly from Iraq and Syria, and that they first felt shock followed by 'a big wave of anger and hurt' when they realised their website had been hacked.

'We have our families still under the threat of ISIS and the majority has been hurt, displaced or raped,' Parish Dergham said.

'I don't think at this stage we have any fear. We've lost everything.

'They [the church members] feel a big loss has happened. We're always hoping that at one stage ISIS would be defeated and we would be back to our towns and churches and monasteries and villages and properties, and business as usual. [But] people have lost hope.'

Parish priest Rahal Dergham told Daily Mail Australia that their church community is mostly from Iraq and Syria. 'We have our families still under the threat of ISIS and the majority has been hurt, displaced or raped,' he said (Our Lady of Mercy Syriac Catholic Church in Concord pictured)

He said the church community had been seeking a peaceful way of life.

'Hopefully Australia will always be a safe country and safe home for all of us.'

The church’s website was restored later on Thursday.

In a Facebook post on Thursday afternoon, the church said they believed the attack had been fuelled by the church’s appeal to help and shelter displaced Syrian and Iraqi refugees.

‘The Islamic State is not happy enough to kill and send the Christians out of their countries but now they want to deny them the help needed to survive once they arrive to this beautiful place we all call home.'

The website made by hackers claiming to be from Islamic State included a link to a website which called the attacks in Paris a 'blessed onslaught'.