"It's the capacity to keep those passports cancelled or the renewal process you have to go through".
"What we are trying to do when it comes to patch that we might put on our legislation is keeping it as narrow as possible. There would a sunset clause in terms of what we'd do and there'd be a small select committee process".
"So we're not trying to broaden this thing out and throw everything into a melting pot and pass things under a cover of what's happening in Iraq and Syria. I think we'll only realistically get the other political parties to join us if we can convince them both that this is necessary and reasonably tight in terms of its focus."
Mr Key said his department had now briefed other political parties on the proposed law changes apart from NZ First.
Mr Key said he understood argument that people who wanted to fight in Iraq and Syria should be allowed to go but not come back, but he said that was not a responsible position to take.
"On the other said of the coin, you're then saying that they're going to potentially undertake those terrorist acts on civilians in other countries and surely we have a responsibility to be a good global citizen."
Meanwhile Mr Key said he expects to make a decision about a New Zealand contribution to the fight against Islamic State probably before he leaves for the Apec meeting which begins on November 8.
Labour foreign affairs spokesman David Shearer who has been briefed on the Government's plans, specifically around the passport issue but not the broader question of whether or not New Zealand should be involved in Iraq.
"We're as eager as anybody to make sure that we have a safe New Zealand so we will be looking at this and working with them (the Government) co-operatively but we would rather that the process was a good one than a rushed one".
Mr Shearer said Labour wanted to see a system where the bar was set very high before anybody's passport was removed.
He indicated Labour was open to supporting an interim measure which included a sunset clause until a fuller review was completed next year, "but let's try and at least have a full process followed" including the chance for submissions on the proposed law.
"If we don't have a full process we make mistakes."