"To all the well spoken people in Aotearoa, u will all need to learn a new english. Its called Hori lol. Cos thats basically all i speak haha [sic]," he tweeted.
Walker was unavailable for further comment last night.
The series continues to be a hit with New Zealand audiences, with 395,500 tuning in on Sunday night, according to Nielsen ratings.
Last night the 12 finalists were announced as Benny Tipene, Tom Batchelor, Whenua Patuwai, Cassie Henderson, Eden Roberts, Jackie Thomas, Anna Wilson, Maaka Fise, Taye Williams, Gap 5, L.O.V.E. and Moorhouse.
In a twist, it was announced the public could vote for a 13th finalist to go through to the Live Shows round of eliminations.