New Zealand outthought South Africa in the field and then Martin Guptill made light work of their bowling as the hosts won the opening Twenty20 in Wellington by six wickets.

The Black Caps are known to be a canny side and Brendon McCullum's outfit were at their very best at the Westpac Stadium as their energetic display in the field helped to restrict the Proteas to 147 for six before Guptill added the fireworks with an excellent knock.

Guptill made five consecutive half-centuries against Zimbabwe in all forms of the game and he continued his rich vein of form with another half-ton.

Fellow opener Rob Nicoll, skipper McCullum and Colin de Grandhomme could only admire his fine innings from the other end and the trio fell relatively cheaply.

It was all about Guptill, though, and he saw his side over the line with an unbeaten 78 from 55 balls with five fours and four sixes.

The difference between the two sides was no doubt the quality of the bowling and the reading of the pitch conditions by the hosts.

While South Africa only had two spinners in Johan Botha and part-timer JP Duminy, the Black Caps used four slower bowlers to strangle the visitors and restrict them.

McCullum's decision to bowl first on a slow track was a good one, especially with his fielders backing up the bowlers and throwing their bodies all over the place.

Guptill produced a 'Jonty Rhodes' as he scooped up the ball and dived full length to run Hashim Amla out while Colin Ingram lasted all of two balls as he danced down the track and found himself dancing back to the dressing room soon after as he was stumped by wicketkeeper McCullum off the bowling of Nathan McCullum.

A lot was expected of debutant opener Richard Levi after his impressive display in the warm-up game against Canterbury and the pressure was perhaps too much as he struggled to get going.

After copping one on the helmet early in the over, he hit Tim Southee down long-off's throat. Skipper de Villiers went a couple of overs later as he hit Ronnie Hira to short cover where Guptill took an outstanding, low catch.

With spinners Nathan McCullum, Kane Williamson, Rob Nicol and Hira cock-a-hoop, South Africa looked set for an average target, but Justin Ontong went bang, bang, bang, bang to give his side's innings impetus.

He got a life when the umpire gave him not out after he appeared to glove one to the wicketkeeper McCullum, and he made the most of it as he took Williamson to the cleaners in the next over.

He smashed the part-timer for four consecutive sixes and suddenly it was the South Africans who were cock-a-hoop. His 17-ball 32 cameo came to an end soon after as Southee took an excellent return catch.