"The fear of cholera and typhoid is our immediate and urgent priority," said Nae'ema al-Gasseer, the WHO's country representative in Iraq.
Millions of Iraqis have been displaced within and without the country since the US-led invasion to topple Saddam Hussein in 2003, and these people are particularly vulnerable to disease risks due to their precarious circumstances.
The WHO opened a permanent office in the Iraqi capital Baghdad last month, after scaling down its operations in the wake of a devastating terrorist attack against the UN headquarters in the city in August 2003.
Gasseer, who works in the permanent office, said being based in the capital enabled her to be "much closer to decision making" and improve cooperation with the Iraqi authorities.
The WHO said earlier this year that an average of 120 Iraqi adults died a violent death every day in the three years following the 2003 invasion.
The WHO estimated the daily death toll by averaging the overall estimates out at 151,000 dead. The survey was based on interviews conducted in 9,345 households in nearly 1,000 neighbourhoods and villages across Iraq.
In 2006, another study by US doctors in the British medical journal The Lancet claimed that 655,000 Iraqis had died as a result of the invasion to topple Saddam Hussein.