All Blacks coach Steve Hansen issued an ominous warning when he said that the runaway Rugby Championship winners can improve.

"We are getting better," he told reporters after New Zealand survived a torrid opening half against South Africa at Soccer City to score 20 unanswered second-half points for a 32-16 triumph and 16 Test victories in a row.

New Zealand visit Australia for a dead Bledisloe Cup rubber on October 20 and face Scotland, Italy, Wales and England on an end-of-season tour to Europe that begins early November.

Facing the Springboks before a large, expectant crowd in the 90,000-seat stadium proved no problem for the world champions as they improved on a 10-point winning margin when the great rivals met in Dunedin last month.

"We know we have some very talented players, but so have a lot of other teams," said the coach who succeeded Graham Henry after hosts New Zealand pipped France for the world title in Auckland last October.

"The difference between us and them is that we are perhaps getting our preparation right during the week and ensuring that our players have the best chance to perform on the Saturday."

Former Wales coach Hansen admitted it had been challenging travelling from New Zealand to Argentina - where they ran in seven tries in a 54-15 romp - and then to South Africa.

"We had to manage the players' workloads carefully," he said, offering a possible explanation as to why the visitors cancelled the traditional eve-of-Test captains' run at Soccer City Friday.

Hansen said juggling with different time zones tested his staff and the players, but he believed the squad "trained smart" ahead of the latest episode in one of the great rugby rivalries.

Captain Richie McCaw said mental strength was a key factor as the All Blacks turned round an early 10-point deficit to make it 16 Tests in a row - two short of the record for a top-tier rugby nation.

"We had the Rugby Championship sewn up last weekend, but the guys understood the challenge of coming to South Africa, and the need to back it up with another victory.

"There are a few guys in our squad who have been around a while and they ensured that we kept our edge. Our fuel tanks probably were not 100 per cent full coming into this game so it came down to mental desire."

South African coach Heyneke Meyer had no excuses.

"The All Blacks really are a quality team and I take my hat off to them, particularly Dan Carter for the way he controlled the game once they were ahead.

"Until half-time we played the right type of game, placing them under pressure. The turning point came when they scored that try soon after the interval as we had to play catch-up.

"They are the best in the world at exploiting and capitalising on turnover ball, and that is what they did with devastating effect in this game," he added.

South Africa, who finished 14 points behind New Zealand in the maiden Rugby Championship, are also off to Europe in November with Tests lined up against Ireland, Scotland and England.

AFP