No 8 So'oialo injured his Saturday's 12-21 loss to the Bulls in Wellington while Weepu twisted his during training this week.
Thomas Waldrom will start at No 8 and Isaac Boss at halfback while there are two other starting changes.
Openside flanker Ben Herring returns in place of Chris Masoe while Conrad Smith comes in at centre, pushing captain Tana Umaga in one place to second five-eighth and Tane Tuipulotu to the reserve bench.
Team: Riki Flutey, Hosea Gear, Conrad Smith, Tana Umaga (captain), Ma'a Nonu, Jimmy Gopperth, Isaac Boss, Thomas Waldrom, Ben Herring, Jerry Collins, Luke Andrews, Ross Kennedy, Neemia Tialata, Andrew Hore, Joe McDonnell. Reserves: Joe Ward, Tim Fairbrother, Kristian Ormsby, Chris Masoe, Shannon Paku, Tane Tuipulotu, Lome Fa'atau.