Barbados-born Bethell, who made his T20 and ODI debuts against Australia last month, has only featured in 20 first-class matches and has a modest batting average of 25.44, with five fifties and no hundreds.
However, England have once again plumped for potential as Smith will be absent for the three-match series, which starts on November 28 in Christchurch, to be at the birth of his first child.
Essex’s Jordan Cox is poised for his Test bow as he deputises behind the stumps for Smith, who has shone with bat and gloves since being thrust into the side at the start of the English summer, ousting Ben Foakes and Jonny Bairstow.
Warwickshire’s Bethell, who turned 21 last week, offers extra batting cover having offered glimpses of his talent in two T20s and five ODIs against a near full-strength Australia.
Bethell also provides occasional left-arm spin to support frontline trio Shoaib Bashir, Jack Leach and Rehan Ahmed, who, alongside Cox, is currently in the Caribbean ahead of a white-ball series against the West Indies. The duo will join the Test team following the end of the tour.
Vice-captain Ollie Pope retains his spot in a 16-strong squad despite underwhelming in the recent 2-1 defeat in Pakistan, amassing 55 runs in five innings with three scores below five.
Pope has made registered three centuries in 2024 – including a stunning 196 against India in Hyderabad in January – but has been dismissed for single-figure scores 11 times in 25 innings.
Ben Stokes offered support to his right hand man after England’s loss in Rawalpindi at the weekend and insisted: “There is no doubt in my mind that we have the best top-six batsmen in England.”
Test head coach Brendon McCullum also made it plain that Pope’s spot to face a Black Caps side, who have handed India their first home series defeat in 12 years, was not up for debate.
McCullum said: “Popey is disappointed with his output of runs. But I’ve said it heaps, number three is a tough place to bat.
“He’ll benefit from a couple of weeks out and he’ll get another opportunity when we head to New Zealand in conditions where he’ll hopefully be able to flourish.”
England squad for Test series against New Zealand: B Stokes (captain), R Ahmed, G Atkinson, S Bashir, J Bethell, H Brook, B Carse, J Cox, Z Crawley, B Duckett, J Leach, O Pope, M Potts, J Root, O Stone, C Woakes.