"There must be competition among other provinces when it comes to rebuilding their regions," he said.
The shrine of Iman Ali, the son-in-law of the Prophet Mohammed, is in the southern city, and other religious sites are nearby.
Developers say that 9 million pilgrims visit the locations each year.
Planners hope that the new airport will increase the number of visitors by 10 per cent annually.
Al-Aqeelah, a Kuwaiti investment firm, has led the multi-billion dollar project. The firm also plans to build thousands of new homes and hotels in Najaf.
Kuwait has a large Shia minority.
Maliki and other government politicians are attempting to promote investment in the country.
Violence in Iraq is at a four-year low following the US-led invasion of the county in 2003.
The UN said that foreign direct investment in Iraq was $272 million in 2006.