Iraqi-Kurdistan's neighbours threaten economic war on Erbil following independence referendum

As Iraqi-Kurds flocked to the polls on Monday for the region's historic independence referendum, neighbouring countries responded with punitive measures including threats of blockade and possible military action.

Key players in the region with their own sizeable Kurdish populations - Iran and Turkey, as well as the Iraq government - staunchly opposed the referendum and warned the Kurdish regional government in Erbil of consequences.

Erbil's neighbours are already taking action. Iran responded on Monday by closing its border with Iraq's Kurdish region, a statement from the country's foreign ministry said.

Airspace and land crossings to the Kurdish territories were closed as voters set out to polling stations to cast their ballots.

Iraq's parliament echoed the Tehran's sentiment by voting to close borders with the country's northern Kurdish regions.

Turkey, which had recently warned that the referendum could result in a global conflict, threatened to cut off the pipeline that carries oil out of northern Iraq. 

Ankara, which views Kurdish separatist militias as terror organisations, has long opposed the referendum and threatened to cut Erbil's lifeline.

"After this, let's see through which channels the northern Iraqi regional government will send its oil, or where it will sell it," Turkish President Recep Tayyip Erdogan said in a speech in Istanbul.

"We have the tap. The moment we close the tap, then it's done."

If the threat is carried out, Ankara would be placing huge economic strain on Iraqi Kurdistan, which exports hundreds of thousands of barrels of oil per day.

Monday's historic poll on Kurdish independence began at 8am, despite warnings from Iraq, Turkey, Iran, the US and the United Nations about the vote.

The referendum is expected to deliver a comfortable victory for the 'yes' camp, however, the result is not binding on Iraq's government, which has already rejected the ballot.

Despite this, a victory for those wanting to see an independent Kurdish state is likely to bolster the region's leader Masoud Barzani's position and strengthen his hand in negotiations with Baghdad.