The Prime Minister is being accused of breaking Cabinet Manual rules by disclosing details about New Zealand's Iraq troop deployment to foreign media.

John Key revealed in Dubai that the troops are in the United Arab Emirates preparing for their Iraq mission.

New Zealand First MP Ron Mark says it appears to him Mr Key's breached rules in the Cabinet Manual about disclosure of official information.

"The Prime Minister, confirmed by the CDF, has made these sorts of details classified information, and now we have him breaching the Cabinet Manual...telling the national media about the deployment of troops."

Mark says Key made it clear just a week or so ago he wouldn't be commenting to the New Zealand public on the deployment because of security reasons.

"Why, having said all that he's said about security, he's then gone and blurted it out to foreign and International media? I just really am struggling right now to understand where this Prime Minister's head is."

Green Party Co-leader Metiria Turei says to reveal this to international media and not tell New Zealanders is a leadership lapse and a serious lack of judgement.

She argues New Zealanders have a basic right to know about our military deployments.

"The Prime Minister has been saying over and over to New Zealanders that he won't tell us what is happening because of security concerns, and yet he'll quite openly talk to journalists from other countries."