The 21-year-old was ushered into the side for the match beginning Thursday after wicketkeeper Jordan Cox broke his right thumb during a net session.
Regular number three Ollie Pope replaces Cox with the gloves and drops down to bat at six, with captain Ben Stokes at seven in the batting order.
Bethell, who has never batted higher than number four in first-class cricket, where he averages 25.44, only made his international debut two months ago in white ball matches against Australia and the West Indies.
Joe Root stays at number four, despite making 262 when he batted third in the first Test in Pakistan last month.
Chris Woakes, Gus Atkinson, Brydon Carse and all-rounder Stokes form the pace attack on a Hagley Oval pitch that traditionally offers a greenish wicket favouring the seamers. Shoaib Bashir is the lone spinner.
New Zealand are yet to name their starting XI but can call on the services of leading batsman Kane Williamson, who has returned after injury forced him out of the recent 3-0 Test series win in India.
England: Zak Crawley, Ben Duckett, Jacob Bethell, Joe Root, Harry Brook, Ollie Pope, Ben Stokes (capt), Chris Woakes, Gus Atkinson, Brydon Carse, Shoaib Bashir.
New Zealand (from): Tom Latham (capt), Tom Blundell, Devon Conway, Jacob Duffy, Matt Henry, Daryl Mitchell, Will O'Rourke, Glenn Phillips, Rachin Ravindra, Nathan Smith, Tim Southee, Kane Williamson, Will Young.
