Authorities on Sunday opened what they billed as the first Christian cultural centre in Iraq in a decade, despite a dramatic decline in the country's once significant Christian population.

The building was inaugurated in the northern city of Kirkuk, home to a diverse population of Arabs, Kurds and Turkmen, and is to host conferences and meetings to promote inter-faith communications between the city's Muslim and Christian communities.

"This centre is the first of its kind in Iraq since 2003, it sends a message of peace, and promotes the language of dialogue," said Louis Sakho, Chaldean archbishop of Kirkuk.

"The communities of Kirkuk are one family," he added.

Construction of the cultural centre, which lies next to Kirkuk's Chaldean church, began in early 2012 and was completed at a cost of around $305,000, officials said.

Iraq's Christian community is one of the oldest of its kind in the world, but they suffered persecution, forced flight and killings in the aftermath of the 2003 US-led invasion.

Before 2003 there were more than a million Christians living in Iraq. Now they number around 450,000.

According to the UN refugee agency, many thousands fled after an October 2010 attack on a church in Baghdad.

From 2003 to May 2012, some 900 Christians were killed, while 200 were kidnapped, tortured and ultimately released for exorbitant ransoms, according to the Hammurabi Human Rights Organisation in Iraq.