Iraqi security forces claim they are poised to take full control of Mosul imminently as Islamic State controls just a few metres of the area, battling to retain the last few streets in a last stand.

"We are seeing now the last meters (of the battle) and then victory will be announced," said a TV speaker, "It's a matter of hours," she said, citing the channel's correspondents embedded with security forces in the Old City of Mosul, by the Tigris river.

According to a Reuters report, a military spokesman said the defence lines of Isis were crumbling. Isis fighters are putting up a fierce resistances with suicide bombers, snipers and grenades, hampering the progress of Iraqi troops. Smoke billowed above Mosul, which was battered by air strikes and artillery fire.

Prime Minister Haider al-Abadi is expected to visit the Iraqi city to formally declare victory, with plans for a week of nationwide celebrations.

Mosul is the largest city seized by Isis and is where the Islamic extremists declared their caliphate.

A post-battle plan to rebuild the city has not yet been formulated. "Prime Minister (Haider) al-Abadi kept dragging his heels. Every time we raised this issue with him, he said, 'Let's wait until military operations are over'," said Hoshyar Zebari, a former finance and foreign minister.

"A whole city is being decimated. Look how much the government is contributing, as if they don't care."