Apart from Lomu, the wing sensation still struggling with a kidney disorder and five-eighth Mehrtens - the most prolific points-scorer in All Blacks history - coach John Mitchell also jettisoned former captains Anton Oliver and Taine Randell and New Zealand's top all-time try-thief, fullback Christian Cullen.
While Oliver, Randell and Cullen were expected to miss the cut and Lomu's battle for fitness left him next to no chance of forcing a place in the final 30-man squad, Mehrtens' axing was the most significant omission.
At the start of the season he was billed as the linchpin of the All Blacks campaign. In 63 Tests he has amassed 932 points, within reach of international rugby's world record held by former Welsh utility back Neil Jenkins.
But the Super 12 form of Carlos Spencer, the injury and fitness troubles Mehrtens struck during the provincial tournament and a decision by Mitchell to alter the All Blacks attacking emphasis combined to bring down the Canterbury Crusaders veteran.
The All Blacks have many five-eighth standbys for Spencer, with regular inside centre Aaron Mauger, rookie Dan Carter and fullback Leon MacDonald and all teammates of Mehrtens at the Crusaders, capable of wearing the No.10 jumper.
Mitchell produced several surprises in his squad, naming three halfbacks and three hookers following an International Rugby Board regulation that only allows teams to replace injured players after a two-day cool-off period.
The edict is designed to ensure northern hemisphere sides are not disadvantaged by travel time in attempting to fly in reinforcements.
Australian-born Steve Devine has been included in the halfback trio while another player who made his name this side of the Tasman, former Brisbane Broncos and Kangaroos rugby league star Brad Thorn, has also won a place in the squad.
Thorn is assured of a heavy involvement in the tournament after Mitchell named only three specialist second-rowers. Ali Williams, Chris Jack and Thorn were expected to be joined in the party by Simon Maling.
But like Otago teammates Oliver and Randell, Maling missed out. His spot went to Auckland's Daniel Braid.
The other is third-choice hooker Corey Flynn, who beat Oliver to the spot behind Keven Mealamu and Mark Hammett.
New Zealand squad:
Backs: Mils Muliaina, Leon MacDonald, Ben Blair, Doug Howlett, Tana Umaga, Daniel Carter, Ma'a Nonu, Caleb Ralph, Joe Rokocoko, Aaron Mauger, Carlos Spencer, Justin Marshall, Steve Devine, Byron Kelleher.
Forwards: Jerry Collins, Rodney So'oialo, Richard McCaw, Marty Holah, Daniel Braid, Reuben Thorne (captain), Chris Jack, Brad Thorn, Ali Williams, Kees Meeuws, Greg Somerville, Keven Mealamu, Mark Hammett, Corey Flynn, Dave Hewett, Carl Hoeft.