The role of New Zealand troops in Iraq is redundant, says Labour party leader Andrew Little.
The government yesterday agreed to leave defence force personnel in Iraq until November 2018.
Four Iraqi soldiers were killed, and more than a dozen people injured, in a suicide bombing yesterday near the entrance to Taji military camp, where New Zealanders are deployed.
No New Zealanders were hurt in the attack. It was the second such attack in ten days.
Mr Little told Morning Report today that New Zealand should not be training Iraqi soldiers, or "propping up" the Iraqi Army.
"The Iraqi army is not making a huge contribution to repelling ISIS, it's being left up to others. The Iraqi army traditionally comes in, does a bit of clean up," he said.
"The forces who are are actually taking cities and creating beachheads and raising the Iraqi flag is not actually the Iraqi army."
Mr Little said he could not say if New Zealand troops would be withdrawn if he were elected Prime Minister next year, as he did not know what the situation would be at that time.
Defence Minister Gerry Brownlee said he expected Islamic State would step up attacks like yesterday's suicide bombing, but the New Zealand troops were as safe as they could be in the high-risk environment.
He said remaining in Iraq was the responsible thing to do.
"New Zealand is not immune to the sort of lone-wolf attack that you saw in Orlando. That guy was not in direct contact with ISIL, but he took his mandate from that particular evil doctrine. So this is as much our war as it is anybody else's."
Mr Brownlee told Morning Report further attacks were likely as Isis loses territory in other parts of Iraq.
"I think one of the things they will try to do is use the influence they have over people who are prepared to lose their lives will be to get them to commit to this kind of incident closer to urban populations trying to keep troops off the front line and protecting things at home."
He would not rule out defence force personnel remaining in Iraq past 2018.