"We have no intention of sending our armed forces into Iraq. Iraq has its own powerful army," Hossein Amir Abdollahian said on a visit to Moscow, although he said the country would be sending military "consultants".
He said Iraq had not yet asked for arms but "in the case that there was such a demand... We would supply the necessary weapons for the fight against terrorism."
Predominantly Shiite Iran has vowed to support ally Baghdad against the Sunni insurgency led by the Islamic State of Iraq and the Levant (ISIL), whose fighters have overrun swathes of five Iraqi provinces since launching an offensive in early June.
Speaking after the Kurdish authorities said they would be holding a referendum on regional independence within months, the diplomat said it was now "vital to take measures to prevent the break-up of the country."
"Instead of daydreaming, the leaders of Iraqi Kurdistan should take a look at the reality," he said.
On Sunday, Sunni insurgents from the Islamic State of Iraq and the Levant (ISIL) announced they were establishing a caliphate in parts of Iraq and Syria where the group has seized control.