James Mortimer 04.Dec.2012Getty Images
This was despite avoiding what is the obvious 'Pool of Death', with Pool A featuring tournament hosts England, the Wallabies and Wales.
Hansen did say increased fixtures against Argentina would ensure the Pumas would not be afraid of facing the defending champions, with the two nations guaranteed to play each other every year in The Investec Rugby Championship.
"I think it will create a bit of excitement around the world and from our point of view we are reasonably happy but a lot of things can change between now and World Cup time so we won’t get too far ahead of ourselves," Hansen said.
"Argentina we will know about because we play them now in a tournament every year so they will be strong as they always are and they will know a lot of about us, that fear factor I guess of each other won’t be as strong."
"Tonga we know they can turn it on on any given moment and if we get them on a night when they want to be really physical then we will have to be on our game, I think there is a enough of a challenge in that pool to get us ready for a quarter-final."
The Tongans were thrilled with being drawn with the All Blacks.
"I think it is the best draw that we ever had," Tonga Rugby Union President Epeli Taione said.
"We couldn’t wish for a better draw for us. The biggest thing for us is a massive relief that we avoid our fellow Pacific Islanders in Samoa and Fiji and now we can just focus on Argentina and New Zealand.
All Blacks captain Richie McCaw said he kept an eye on the pool of death, and said it was good the team now knew who they had to play during the pool stages.
"I think we're reasonably happy, I suppose when they came to drawing out those last four teams I was pretty happy New Zealand didn't come out where Australia did but it is what it is and you have got to deal with whatever is put in front of you," he said.
"We will have our own challenges whoever we play with Argentina and Tonga and then you earn your way through the next one. You have just got to get it right whatever is ahead of you.
"A little bit (of holding his breath when band one team being drawn for Pool A), but had I been standing there and we had been in that pool then you go, well that is what you have got to deal with and if you are going to win it you have got to be good enough to deal with it. That is the way it is."