UPDATED 5.07PM: The Defence Force has been given the go ahead to train troops for deployment to Iraq and join the fight against the Islamic State group.

The Government has yet made a decision on whether a a contingent will be sent to provide training support for Iraqi forces, though a call is expected to be made by the end of this month.

Defence Minister Gerry Brownlee says approval's been given for training to commence at the Linton and Waiouru Army bases.

He says the decision doesn't pre-empt any decision to deploy, but is prudent given final advice on a possible mission is almost complete.

"We're not rushing into anything here," Brownlee says.

"Despite what our opponents might think we're being extremely cautious."

Force protection is also on the cards to defend any troops there. 

"If we've got trainers and they're engaged in the daily activity of training people, they need to make sure there's someone watching their back - that's what force protection is." 

Meanwhile, heated debate over the possible deployment of New Zealand troops to Iraq has dominated Parliament's first day back.

Labour MP Jacinda Ardern says the government still hasn't made the case for what the troops could change for the better.

"The question is not whether or not the international community should react," she said.

"Of course we should. The question is what the most effective course of action."

United Future leader Peter Dunne made a passionate plea for New Zealand to stay out of the fight against Islamic State.

In his first statement to Parliament for the year today, he says history shows intervention in the Middle East only ends in failure, and more intensive division than was there to begin with.

Mr Dunne says statements by the British Foreign Secretary shouldn't sway New Zealanders.

"Here is the patronising figure from abroad loftily telling us that we're part of the club and part of the family and it would be lovely to have you along for the latest unmitigated slaughter is simply unacceptable."