Brendon McCullum said he expected a stiff challenge from the opposition's seam attack when New Zealand face South Africa in their World Twenty20 Super Eights clash in Bridgetown, Barbados.

The Proteas' pace attack completely overpowered tournament sign-offs Afghanistan on Wednesday, with Morne Morkel, Charl Langeveldt and Dale Steyn claiming four, three and two scalps respectively in a comprehensive 59-run win and pose an entirely different threat than spin-laden Sri Lanka and Zimbabwe, who the Kiwis beat earlier in the tourney.

"South Africa's a quality team, everyone knows that," McCullum said.

"We've all seen how good they are in all three forms of the game and in Twenty20 they've got some dangerous players right through the line-up and they offer a different challenge to what Sri Lanka and Zimbabwe have offered us so far with a bit more predominant seam attack."

New Zealand's wins over Kumar Sangakkara and Prosper Utseya's men came on the low, slow pitches in Guyana, where the batsmen initially struggled to familiarise themselves with conditions.

But McCullum believes the move to the Kensington Oval will offer the Kiwis' top order a distinct advantage.

"The pitches in Guyana were a little more conducive to the slower bowling which probably doesn't suit out batsmen quite as much but while it wasn't flash and wasn't flamboyant we got the job done in both games," McCullum added.

"I think the wickets in Barbados will be a little bit quicker and it will present an opportunity for us top-order batsmen to play with a little freedom as well and hopefully we will see one, or two, or three of the top four go on and make some sizeable totals in the next few games."