Munro is in prime form and is a classic example of trying someone when they are on song, rather than dithering.
Dean Brownlie is recalled, as expected, and given the makeup of the squad is likely to go straight into the No5 or 6 spot for the first test at Cape Town, starting on January 2.
Ross Taylor's absence opened a hole - in more ways than one. Fulton, last sighted in a test side three years ago, but in strong domestic form, is back. That may be owed to a mix of picking batsmen with numbers to their name, plus the need for another senior figure.
Take away Taylor and Fulton and it is a seriously skinny batting group in years. Somehow James Franklin has kept his place in both squads.
Martin's credentials - 297 wickets at 35.2 - don't exactly roar "pick me". However, he deserves an opportunity. Dan Vettori is out injured and legspin, in the form of Todd Astle, was not what the selectors, coach Mike Hesson and Kim Littlejohn, wanted.
The five seamers hold their places from Sri Lanka but there will be a different face wearing the big gloves in their line of sight, with BJ Watling taking Kruger van Wyk's keeping spot in the test squad.
Van Wyk owed his test selection to an injury to Watling on the eve of the first test against South Africa in Dunedin last season. He had held it since, but his form was unconvincing. A pair in the Colombo win didn't help.
Watling is a popular figure but must score runs. He has eight first-class hundreds, including one in a test against Zimbabwe last season, and averages 34.
Tour squads
New Zealand squads to tour South Africa:
Tests: Brendon McCullum (c), Martin Guptill, Peter Fulton, Kane Williamson, Daniel Flynn, Dean Brownlie, James Franklin, BJ Watling, Doug Bracewell, Jeetan Patel, Tim Southee, Bruce Martin, Neil Wagner, Trent Boult, Chris Martin
T20: Brendon McCullum (c), Guptill, Rob Nicol, Fulton, Franklin, Corey Anderson, Jimmy Neesham, Colin Munro, Nathan McCullum, Derek de Boorder, Bracewell, Ronnie Hira, Adam Milne, Mitchell McClenaghan, Boult.