Wyatt Roy, a former assistant minister and Australia's youngest ever MP, lost his seat in the July election.
He travelled to the front line of the conflict between the Islamic State group and Kurdish forces, in defiance of travel warnings, to "see a mate".
Five IS fighters were reported to have been killed last week in the battle, west of Mosul.
IS fire fight
Mr Roy said he was at the frontline "for no more than a minute" when 15 IS fighters fired a series of 50-calibre rounds and RPGs from less than 1km away.