The Hamilton East MP takes over the role from Muller, who relinquished it in favour of the small business portfolio when he deposed former leader Simon Bridges on May 22.
Rangitata MP Andrew Falloon has been named associate agriculture and biosecurity spokesman, Taranaki-King Country MP Barbara Kuriger is the party’s rural communities spokeswoman and Clutha-Southland MP Hamish Walker is the spokesman for forestry and land information.