Morkel, 38, was recently part of the Namibia men's coaching staff during the 2022 T20 World Cup in Australia, and is presently a bowling coach with Durban's Super Giants in the SA20 League. He will join the New Zealand women's team before their first game of the T20 World Cup, against Australia.
"The women's game is growing so rapidly around the world, and this a great opportunity for me to build experience in the women's game and share my knowledge of international cricket to help this team get better," Morkel said. "I've been following the women's game and the WHITE FERNS closely over the last couple of years, especially since moving to Australia and seeing their players who have played in the Women's Big Bash.
"It's a talented group of players and they have a very exciting pace bowling attack which I'll be able to support Ben [Sawyer] with. I know a lot about the South African conditions and have spent a lot of time working here in the past year, so that' some important knowledge that I'll be able to share with this group during the tournament.
Morkel played 86 Tests, 117 ODIs and 44 T20s for South Africa between 2006 and 2018, and also has experience of playing in T20 leagues around the world.
New Zealand will name their squad for the T20 World Cup on January 20 and the players will depart for South Africa on January 23.
They are in Group A in the first round of the tournament and play Australia on February 11, followed by South Africa (February 13), Bangladesh (February 17) and Sri Lanka (February 19).