President Recep Tayyip Erdogan on Thursday warned that Turkey would "soon" close its border crossing with Iraqi Kurdistan and airspace after the disputed referendum on independence.

Iraqi Kurdish leaders went ahead with the September 25 poll on independence despite fierce objections from neighbouring countries including Iran and Turkey.

"Air space will be closed ... the border will also be shut soon," Erdogan said in a televised speech. "How will you (the Iraqi Kurds) have imports and exports then?" he added.

"The clock is ticking against them," said Erdogan.

In the wake of the non-binding poll, which was overwhelmingly won by the 'Yes' camp, Erdogan has repeatedly told Arbil the Habur border crossing would be closed but this has yet to happen.

Turkish carriers have already suspended their flights to Iraqi Kurdistan, although this was in line with an order from Baghdad rather than a reprisal from Ankara.

Turkey fears the vote will embolden its own sizeable Kurdish minority, and is eager to work with Iran and the central government in Baghdad to block it.

Erdogan's comments came a day after a key visit to Tehran where both countries presented a united front in their opposition to Iraqi Kurdish aspirations of independence.

He reaffirmed his belief that only Israel was in favour of Iraqi Kurdish independence. "They are not your friends," he said.

But some analysts argue Turkey will be wary of cutting off economic ties with Iraqi Kurdistan as this risks hurting the domestic Turkish economy.

Erdogan's ruling Justice and Development Party (AKP) government has forged close ties with Iraqi Kurdish leader Massud Barzani, enjoying burgeoning trade ties and Arbil exporting the region's oil through the Turkish port of Ceyhan.