New Zealand cemented their position at the top of the Tri-Nations table with a five-try victory over South Africa in Wellington.

Doug Howlett, Mark Hammett, Tana Umaga, Justin Marshall and Scott Robertson were all on the scoresheet as the All Blacks followed up last week's win over Australia.

John Mitchell's side went in front through an early Andrew Mehrtens penalty but did not take full control of the game until late in the first half.

South Africa took a 10-3 lead thanks to a fine individual try from full-back Werner Greef and a conversion and penalty from Andre Pretorius.

Mehrtens' second three-pointer was cancelled out by a Greef drop goal before New Zealand pressure told with a try for Howlett that Mehrtens converted for 13-13 midway through the half.

And the All Blacks reached the interval in the driving seat as a try from a line-out by hooker Hammett and a Mehrtens penalty put them 21-13 in front.

New Zealand effectively ended the contest in the opening 10 minutes of the second half.

Mehrtens dropped a goal before converting an Umaga try scored courtesy of a lucky bounce while chasing a kick.

That put the hosts 31-13 ahead, although Marius Joubert replied immediately by cashing in on an Umaga mistake.

However, the Springbok outside-centre was sent to the sin-bin two minutes later for a high tackle and violent conduct, effectively killing any slim hopes of a South African comeback.

Howlett set up a try for Marshall in Joubert's absence, and Robertson charged over late on to take New Zealand through the 40-point barrier.

The try-scoring bonus point the All Blacks took from the game gives them an eight-point lead over Australia in the Tri-Nations table.

The Wallabies take on South Africa in Brisbane next Saturday.

New Zealand: C Cullen; D Howlett, M Robinson, A Mauger, C Ralph; A Mehrtens, J Marshall; S Robertson, Richard McCaw, R Thorne (capt); S Maling, C Jack; G Somerville, M Hammett, D Hewett. Replacements: T Willis, J McDonnell, R Willis, S Broomhall, B Kelleher, T Umaga, J Lomu.

South Africa: W Greeff; S Terblanche, M Joubert, D Hall, DW Barry; A Pretorius, J Conradie; B Skinstad, J van Niekerk, J Labuschagne; V Matfield, C Krige (capt); W Meyer, J Dalton, L Sephaka. Replacements: O le Roux, Faan Rautenbach, AJ Venter, H Scholtz, N de Kock, A Jacobs, B Paulse.

Referee: Stuart Dickinson (Aus)