General Jabar Yawer, secretary general of the Peshmerga ministry, told AFP news that "there are no PKK forces in Kirkuk, but there are some volunteers who sympathise with the PKK".
The Iraqi and Kurdish sides have exchanged angry words since Kurds on September 25 voted overwhelmingly for independence in a referendum that Baghdad refused to acknowledge.
Iraqi security forces have launched a "major operation" in Kirkuk to take control of a strategic Kurdish military base and oil fields, according Kurdish and Iraqi officials.
The central government in Baghdad has taken a series of measures to isolate the Kurdish region since they held a referendum on independence, including banning worldwide flights to the area.
Iraqi Prime Minister Haider al-Abadi has said there can be no further discussion of the Kurds' longstanding demands to incorporate Kirkuk and other historically Kurdish-majority areas in their autonomous region until the independence vote is annulled.
Iraqi forces and Shi'ite paramilitaries, known as Popular Mobilisation, are deployed south and west of Kirkuk, in areas previously under the control of Islamic State.
An Iraqi military spokesman denied the KRG claim.
"We can't turn on each other right now". US coalition spokesman Ryan Dillon told The Associated Press that military movements in the region were in line with recent operations to clear the terrorist group's fighters from Hawija, a town roughly 40 miles west of Kirkuk.
Iraqi forces captured Mosul from Islamic State in July, after a grueling nine-month US -backed offensive with the participation of Kurdish Peshmerga.
The two main highways connecting Erbil and the city of Douc with Mosul, the second city of Iraq, remain blocked by Peshmerga.
Abadi's government, seeking to keep the country together, has taken measures to isolate the KRG, including a ban on direct worldwide flights to the region.
The referendum was held in three autonomous provinces of Iraqi Kurdistan, but also in nearby Kurdish-held areas including Kirkuk. Neighboring Iran and Turkey back Baghdad's stance, fearing the spread of separatism to their own Kurdish populations.