Forces including federal police and the interior ministry’s elite Rapid Response moved in convoys towards the disused airport, which lies on the southern approach to Mosul and is still held by the Islamic State group.
They fired a barrage of mortar fire while attack helicopters and other aircraft cleared the way for ground troops, an AFP correspondent reported.
The US-led coalition has played a key role in supporting Iraqi forces with air strikes and advisers on the ground, and on Thursday US forces in armoured vehicles were moving on the airport with Iraqi forces.
“We will reach it today God willing,” Brigadier General Abbas al-Juburi of the Rapid Response force told AFP just over a kilometre (less than a mile) from the airport.
Thousands of security personnel on Sunday launched a fresh push in their four-month-old offensive to retake Mosul, the second city and the last stronghold of the jihadists in Iraq.
They started closing in on the airport four days ago. It is unclear how many jihadists are defending the airport but US officials said Monday that only around 2,000 remain in Mosul.
Government forces blitzed through some of the last open areas between their lines and the city limits on the west bank of the Tigris River which runs through Mosul and elite troops are expected to enter the west of the city in the coming days.
Iraqi forces declared the eastern half of Mosul fully liberated exactly a month ago.