Weepu's selection was always going to be the most contentious given his below-par performances for the lacklustre Blues this season, along with his obvious lack of physical conditioning.
Hansen has picked Aaron Smith from the Highlanders as his other halfback, which means in-form Crusader Andy Ellis misses out.
The selection of Smith, a promising 23-year-old who is yet to play a test, had been signalled by Hansen, so it was barely a surprise when his name was read out in Auckland today by New Zealand Rugby Union president Bryan Williams.
The picking of Weepu was probably more controversial and Hansen called on the 56-test player's record as the main justification for it.
"We see Aaron Smith as similar to a guy called Graeme Bachop, a great passing halfback,'' Hansen said. "He brings something that we haven't had for a wee while. Then we wanted to keep some experience so it came down to either Piri or Andy and we just felt that Piri's added ability to goalkick and play first-five if we got a double injury in the course of a game as we got in the [World Cup] quarter-final in 2007, they're advantages.
"Piri is also the incumbent No1 All Blacks halfback who played extremely well at the World Cup. And without him I think we may have struggled to achieve what we achieved, especially losing Dan and Colin Slade during the quarter-final period. We acknowledge, and he would acknowledge also, that he probably hasn't been in the greatest form.
"We set him some strong targets at the camps and he's met those and he's now in better condition than he was in the World Cup. He's very highly motivated and that gives us the confidence that we'll get the Piri Weepu that we know and we all love in the past.''
Weepu played no part in last night's 41-34 win by the Chiefs over the Blues at Albany. He had been named on the reserves bench and stayed there, but that was due to a tight hamstring and Hansen thanked Blues coach Pat Lam for not risking him.
Hansen added of Weepu: "He's a competitive spirit and the bigger the occasion the bigger he steps up. He's proven that and hence why we've stuck with him. He's working particularly hard at getting fitter. He acknowledges himself that he let himself down in that area. But we're confident he will produce the goods for us.''
The door is not completely closed on 28-year-old Ellis. Injuries could bring a reprieve for someone who also played well at the World Cup but, although the selectors will name three halfbacks for the end of year tour, they could put their faith in another up-and-comer such as Tawera Kerr-Barlow or TJ Perenara, who did not make the initial All Blacks squad.
Hansen said he wanted to build towards the 2015 World Cup which suggested his mind is on younger, rather than older, players. The selection of Hika Elliot ahead of Corey Flynn as injury cover for hooker Keven Mealamu also points to that.
The squad features seven new caps, including three players from the Chiefs' forward pack _ prop Ben Tameifuna, loose forward Sam Cane and lock Brodie Retallick. Crusaders and Canterbury lock Luke Romano is also a new cap in the forwards.
The new caps in the backs are Highlanders halfback Smith, and the Hurricanes duo of Beauden Barrett and Julian Savea.
The squad is made up of 10 Crusaders, six Highlanders, four Hurricanes, five Chiefs and five Blues. It will be once again led by 31-year-old Richie McCaw and is made up of 16 forwards and 14 backs, with a combined total of 879 test caps.
Unavailable for selection due to injury include wider training group player Charlie Faumuina (calf), Anthony Boric (neck), Cory Jane (ankle), Richard Kahui (shoulder), Jerome Kaino (shoulder), Colin Slade (leg) and Isaia Toeava (hip).
The squad assembles in Auckland today to prepare for the first test against Ireland next Saturday at Eden Park.
The 30-player All Blacks squad named today, with test caps in brackets, is:
Forwards
Hookers: Andrew Hore (62), Keven Mealamu (92); props: Wyatt Crockett (6), Ben Franks (15), Owen Franks (31), Ben Tameifuna (0), Tony Woodcock (83); locks: Brodie Retallick (0), Luke Romano (0), Sam Whitelock (25), Ali Williams (73); loose forwards: Sam Cane (0), Richie McCaw (c) (103), Kieran Read (36), Adam Thomson (24), Victor Vito (13);
Backs
Halfbacks: Aaron Smith (0), Piri Weepu (56), first-fives: Beauden Barrett (0), Dan Carter (85), Aaron Cruden (9); midfielders: Tamati Ellison (1), Ma'a Nonu (66), Conrad Smith (55), Sonny Bill Williams (14); outside backs: Israel Dagg (12), Hosea Gear (8), Zac Guildford (8), Ben Smith (2), Julian Savea (0).
Hooker Hika Elliot (2) has been included as injury cover.
