Maliki, a former prime minister who remains very influential, lashed out at Erdogan after Turkey shot down a Russian jet it said briefly violated its airspace during operations in northern Syria on Tuesday.
"Erdogan claims that a Russian aircraft entered Turkey's airspace for a few seconds, forgetting that its own planes violate Iraqi and Syrian airspace every day," he said in a statement.
Turkish fighter jets have in recent months carried out a series of deadly strikes against rebels of the Kurdistan Workers' Party (PKK) in their bases in the north of Iraq.
Signup to our newsletter and follow us on Facebook and Twitter!
"Erdogan's double standards and aggressive policies are threatening a new world war," he said.
The authorities in Baghdad have long accused Ankara of playing a key role in the rise of the Islamic State group, which took over entire regions of Syria and Iraq over the past two years.
Maliki and his allies among Tehran-backed Shiite militia groups battling IS jihadists see Moscow as a key ally and have welcomed Russia's growing involvement in the regional conflict.
The downing of the Russian jet has threatened ties between two major rival players in the Syrian war and raised fears it could fuel wider geopolitical conflict, although both Ankara and Moscow have stressed they want to avoid military escalation.