Smith claimed 24 wickets across both white-ball competitions for the Firebirds last summer, including career-best T20 figures of 4-5 against the Otago Volts in Alexandra in the Dream11 Super Smash.
Hay, who debuted for New Zealand A last year, has been a consistent performer across all three formats in recent seasons with the 24-year-old crowned Canterbury’s male Player of the Year in April.
The pair join a fresh looking Black Caps squad, made up of a host of experienced internationals and a selection of newer faces who have made international debuts in the past two years.
Lockie Ferguson will spearhead a pace bowling group featuring Duffy and Canterbury’s Zak Foulkes, alongside all-rounders Smith and Josh Clarkson.
Powerful Wellington Firebirds opener Tim Robinson earns his second call-up after excelling on his maiden international voyage to Pakistan in April, along with Clarkson who impressed in last summer’s ODIs against Bangladesh.
Leg-spinner Ish Sodhi is the most experienced T20I player in the squad with 117 appearances.
Michael Bracewell and Glenn Phillips are the spin-bowling all-rounders, alongside Santner, while Dean Foxcroft offers some off-spin alongside his specialist batting skills.
The experience of Phillips, Will Young and Henry Nicholls bolsters the batting, with Nicholls coming off an impressive Ford Trophy campaign last summer where he scored 301 runs in six games at 75.25.
