New Zealand headed for South Africa Sunday knowing they are just one point away from sealing another Rugby Championship title.

Right-wing Ben Smith scored 27 seconds from time in La Plata Saturday to grab a four-try bonus-point 33-15 victory over spirited but unimaginative Argentina.

The latest All Blacks triumph came 10 hours after the Springboks outplayed Australia 28-8 in Cape Town, but scored only three tries and missed a bonus point.

After the penultimate round of southern hemisphere championship league matches, title-holders New Zealand have 23 points, South Africa 18, Australia four and Argentina two.

To snatch the title from their greatest foes, the Springboks must win and score at least four tries in Johannesburg next weekend while preventing the All Blacks collecting any points.

New Zealand coach Steve Hansen told a media conference in La Plata that the situation going into the final round suits his world champions.

"They are going to have to play some rugby to get four tries and that will suit us as much as it will suit the Springboks," he said.

"Our guys are looking forward to this match -- they are already starting to talk about it so I don't think there will be any problem getting them motivated."

All Blacks No. 8 and skipper Kieran Read said the clash with fellow two-time world champions South Africa was a challenge he relished.

"It is going to be a big match next weekend. We face a long flight and then we must recover and prepare for the Springboks," he said.

New Zealand have to decide whether flank and first-choice captain Richie McCaw will be fit -- he travelled to Argentina as part of the squad but did not play.

Adding spice to the Ellis Park Test is the controversial red-carding of South African hooker Bismarck du Plessis when they lost 29-15 to the All Blacks in Auckland this month.

Du Plessis was wrongly sin-binned during the first half after a legal tackle on star fly-half Dan Carter and another yellow card soon after half-time triggered automatic expulsion.

The hooker did not start against the Wallabies, but Springboks coach Heyneke Meyer said he will be in the Ellis Park starting line-up.

However, South Africa may lack Flip van der Merwe, who has been cited after pushing his elbow into the face of Australian wing Joe Tomane.

French referee Jerome Garces showed the lock a yellow card, but the citing commissioner said in a statement that the incident met the red-card threshold for foul play.

Argentina, still seeking a first Championship win after 11 Tests spanning two seasons, led New Zealand three times before early second-half tries from flank Sam Cane and Smith turned the tide.

A two-point advantage became a 26-12 lead and although fly-half Nicolas Sanchez cut the deficit with his fourth penalty, Smith had the final say.

The Pumas host fellow strugglers Australia in Rosario next Saturday and skipper and No. 8 Juan Martin Fernandez Lobbe is cautiously optimistic.

"It is very frustrating for us not to get that first victory, but we are growing and it will come. Let us hope Australia have a bad day and we have a good one."