Overnight Peter Lawrie found the going tougher on the Golf De L'Océan course after a sparkling opening 64 at Golf Du Palais Royal - the field play both courses in a pro-am format over the first two rounds.
The Irishman dropped four shots early in his second round, bogeys at the third and fifth followed by a double-bogey five on the par three seventh as he slipped back to four under.
That allowed Coetzee to march into a two shot lead as he completed his first eight holes on the Golf Du Palais Royal layout in four under par after a four under 67 opening round.
The 24 year old started with two birdies after teeing off the tenth, added further gains on the 13th and 15th and responded to his first bogey of the day on the 16th by picking up a shot at the 17th.
At eight under he was two clear of defending champion Rhys Davies - the Welshman one under for the day through ten at De L'Océan - and India's Shiv Kapur, who was one under through seven at the same venue.
English duo David Horsey and James Morrison, both playing at Palais Royal, were tied for fourth on five under.