As the Australians departed South Africa for a series in Bangladesh, the New Zealanders arrived in Johannesburg on Wednesday.
They play a four-day warm-up against a Rest of South Africa XI starting in Benoni Friday, with the first Test starting at Centurion on April 15.
New Zealand are fifth in the International Cricket Council Test rankings, one place above South Africa, but Black Caps captain Stephen Fleming said he didn't regard his team as favourites despite the hosts having lost all three home Tests against Australia.
"South Africa will be tougher than normal after a long series against Australia," said Fleming.
"South Africa are always a tough side to play, especially at home, and so we won't be reading too much into the outcome of the series against Australia."
New Zealand were beaten 4-0, with a fifth match rained out, when they played a One-day series in South Africa in October.
The One-day and Test tours were split because of the ICC Super Series in Australia. It means the Tests will take place after the end of the normal South African season. Chilly weather and fading light could be a factor, although Fleming said that conditions could be similar to those in New Zealand.
"We have fairly cold summers, so we'll be geared for it," he said.
Fleming said he believed New Zealand had brought a strong squad to South Africa, highlighting the inclusion of fast bowler Shane Bond, whose form in a recent series against the West Indies showed he was back to full fitness after a long battle against injury, and fit-again all-rounder Jacob Oram.
A key issue for New Zealand could be the form of their top order batsmen, with the likely first three, Michael Papps, Jamie How and Peter Fulton all relatively inexperienced.
They will have to combat an in-form South African fast bowler Makhaya Ntini, who took 19 wickets in the three-match series against Australia.
The South African players dispersed immediately after their two-wicket defeat in the third Test against Australia Tuesday and will have a complete rest from cricket until they assemble before the first Test against New Zealand.
Jacques Kallis, who captained South Africa in the third Test against Australia in the absence of the injured Graeme Smith, admitted: "There is that danger that we've played some hard cricket and the guys might not be ready but we've been given 10 days off to get mentally prepared for New Zealand.
"It's a huge series for us. It's a series that could define our season. If we play some good cricket and win well it might not be as bad a season as it looks. We're going to be taking it very seriously."
The Rest of South Africa team that will play against the tourists in Benoni will provide reasonable opposition. The side is led by former Test batsman Neil McKenzie and includes eight other players who have played for South Africa, either at Test or One-day level.
New Zealand squad: Stephen Fleming (capt), Daniel Vettori (vice-capt), Nathan Astle, Shane Bond, Peter Fulton, James Franklin, Jamie How, Brendon McCullum, Hamish Marshall, Chris Martin, Kyle Mills, Jacob Oram, Michael Papps, Jeetan Patel, Scott Styris
Coach: John Bracewell