However, Labour's Phil Goff says Mr Key himself was misleading the public by insisting that New Zealand Chief of Defence Force Lieutenant General Tim Keating was attending a "regular" meeting of defence chiefs -- where Islamic State was the only item on the agenda.
The meeting of military chiefs from various countries, including General Keating, at Andrews Air Force Base was addressed by US President Barack Obama. Mr Key said he had been assured by the Defence Force it was just "a regular meeting the CDF always goes to".
International media billed it as a meeting of the anti-Isis coalition and an official report from the US Department of Defence described it as a meeting "to co-ordinate strategies in the fight against Islamic State of Iraq and the Levant terrorists".
"It's true that one of the topics of conversation will be what contributions countries might make although that is not the purpose of the meeting as I understand it," Mr Key said.
New Zealand has so far committed only humanitarian aid to those suffering as a result of the conflict.
The Defence Force yesterday afternoon continued to insist the meeting was a "regular" one but did not respond to requests for its title or details of previous meetings.
A spokeswoman later confirmed General Keating's presence was "part of the information-gathering exercise being undertaken by New Zealand officials to enable them to develop comprehensive advice to Government on countering Isis".
Labour MP and former Defence Minister Phil Goff said it was "most certainly not a regular, normal meeting".
"The Pentagon itself is saying that this is a meeting of coalition countries to determine what each country can do in a military campaign against Isis."
Mr Goff said he had until now accepted Mr Key's assurances he would consult about any potential military involvement in the conflict.
"It just seems to me that all this talk which I've accepted in good faith actually is just political spin and the decision actually has already been taken.
"The Prime Minister's playing fast and loose with the truth on this one. I'd like to think we could trust the Prime Minister on matters as serious as committing our troops to a conflict where some may not return but the argument does not stack up as he is trying to portray it."
By Adam Bennett of the New Zealand Herald
