South Africa scored nine tries in a predictably one-sided drubbing of neighbours Namibia in their second Rugby World Cup outing.

Hooker Mbongeni Mbonambi ploughed over for two scores as the Springboks built a 28-point lead by the interval.

There was no let-up after the break with Warrick Gelant going over before scores for Makazole Mapimpi, Siya Kolisi and Schalk Brits.

Namibia's only points came via a solitary penalty from Cliven Loubser.

Things will not get any easier for the lowest-ranked side in the Rugby World Cup - in their next encounter, in eight days' time, they meet world number ones and two-time defending champions New Zealand in Tokyo.

South Africa's next match is a meeting with Italy in Shizuoka on Friday.

Springboks run rampant

After the bruising 23-13 defeat to the All Blacks in their opening match of the tournament, South Africa coach Rassie Erasmus made 13 changes to his starting XV with only Lukhanyo Am and Makazole Mapimpi retaining their places.

It allowed Erasmus to take a look a some options that he may need later in his campaign, such as back-row fetchers Kwagga Smith and Francois Louw, and others that are unlikely to be required, like 38-year-old hooker Schalk Brits reprising a number eight role he last played a decade ago.

The Springboks duly used the match to polish up their drills and skills for tougher tests to come, with a couple of driven line-outs proving irresistible in the first half and full-back Warrick Gelant rounding off a superb counter-attack score early in the second half.

Defence coach Jacques Nienaber had promised before the match that there was "no points limit" set for South Africa, but Namibia's stubborn defence was unbroken in the final 17 minutes as the contest lost shape and rhythm.

Namibia close the gap, slowly

The defeat may have been heavy, but Namibia, whose squad is made up of 70% amateurs, are getting closer to their powerhouse neighbours.

In 2007 and 2011, their only previous meetings with South Africa, they lost by 92 and 87 points respectively.

The 54-point margin might have been slimmer had replacement Johannes Coetzee not been sin-binned for a blatant shoulder charge on Brits.

Their improvement could also be in part attributed to their opponents, Namibia having trained with South African provincial side Sharks and been invited into the second tier of South Africa's domestic Currie Cup competition.