DURBAN, South Africa, Jan 11, 2013 (AFP) - The former British Open champion birdied eight holes -- five on the front nine and three on the journey back -- and did not drop a shot for a 64 and a halfway 132 total.
Oosthuizen is one stroke ahead of Scott Jamieson and first round leader Thongchai Jaidee. The Scot also returned a 64 over the 6,111-metre course while the Thai had a 68, three shots more than he took Thursday.
There is a six-shot gap between the leader and those tied for fourth place on 139 -- Dane Thomas Bjorn, Julien Quesne of France, Scot Paul Lawrie, Danny Willett of England, Indian Jeev Milkha Singh and Shane Lowry of Ireland.
Reigning British Open champion Ernie Els of South Africa, Belgian Nicolas Colsaerts and Francesco Molinari of Italy are a stroke further back in the 33-man field.
Defending champion Branden Grace of South Africa, winner of five European Tour events last season, atoned for a disappointing opening 75 with a 67 that placed him on 142, nine strokes behind the leader.
Oosthuizen finished the outward nine strongly with three consecutive birdies and had two more on 17 and 18 in a round notable for good recovery shots from the rough after only seven of his 14 tee shots found the fairways.
Jamieson seems to enjoy the Indian Ocean city as he won the Nelson Mandela Championship -- shortened to two rounds by torrential rain -- at another Durban course last month..
Birdies at two, three and four got his round off to a flying start and two more enabled the Scot to turn in 31 before the only slip, a bogey five at 10, was followed by another four birdies.
An eagle three at the eighth was the highlight for ex-paratrooper Thongchai, who also had three birdies and a bogey as he pursues a sixth European Tour title.
Former victorious Ryder Cup captain Colin Montgomerie of Scotland had a round to forget with his 78 including six bogeys and one double bogey and he lies second last, two shots ahead of Portuguese Ricardo Santos.
The Volvo Golf Champions is restricted to 2012 European Tour winners and those with more than 10 career titles on the circuit, and there is no halfway cut because of the small field.
Full scores after second round of the Volvo Golf Champions tournament at par-72, 6,111-metre Durban Country Club Friday:
132 - Louis Oosthuizen (RSA) 68-64
133 - Scott Jamieson (SCO) 69-64, Thongchai Jaidee (THA) 65-68
139 - Thomas Bjorn (DEN) 69-70, Paul Lawrie (SCO) 69-70, Shane Lowry (IRL) 70-69, Julien Quesne (FRA) 72-67, Jeev Milkha Singh (IND) 69-70, Danny Willett (ENG) 69-70
140 - Nicolas Colsaerts (BEL) 73-67, Ernie Els (RSA) 68-72, Francesco Molinari (ITA) 70-70
141 - Rafa Cabrera-Bella (ESP) 72-69, Jamie Donaldson (WAL) 69-72, Padraig Harrington (IRL) 70-71
142 - Retief Goosen (RSA) 72-70, Branden Grace (RSA) 75-67, Richie Ramsay (SCO) 69-73, Henrik Stenson (SWE) 72-70
143 - Paul Casey (ENG) 74-69, Darren Clarke (NIR) 75-68
144 - Matteo Manassero (ITA) 75-69, Robert Rock (ENG) 70-74
145 - Gonzalo Fdez-Castano (ESP) 75-70
146 - Michael Hoey (NIR) 72-74, Jose Maria Olazabal (ESP) 74-72
147 - Thorbjorn Olesen (DEN) 75-72, Bernd Wiesberger (AUT) 76-71
148 - Darren Fichardt (RSA) 78-70, Jbe Kruger (RSA) 75-73, Marcel Siem (GER) 74-74
150 - Colin Montgomerie (SCO) 72-78
152 - Ricardo Santos (POR) 76-76
Note: no halfway cut because of limited field