Duffy, who has played 23 white-ball games for the Black Caps, will help compensate for the retirement of the long-serving Joe Leach next season in the Worcestershire attack.
Head coach Alan Richardson said Duffy’s signing as their first overseas recruit will give the squad a boost.
“It feels like we are getting someone who is highly skilled, experienced and a very robust cricketer,” he said., external
“With there being no Joe [Leach], it was important to see how we try and fill that gap in different ways.
“We also know from doing diligence that Jacob is an outstanding character which is really important in terms of how they fit in, how they work with the current players.
“We’ve not only got a skilful cricketer but also an outstanding individual as well so that is really exciting for us.”
Duffy’s spell at New Road will start against Yorkshire at Headingley on 11 April, after the opening match of the season at Somerset a week earlier.
