The German's two-round aggregate of 129, 15 under par, left him four shots ahead of Rolf Muntz, the Dutchman following a 68 wih a 65. Ireland's Paul McGinley and Brendan McGovern were a shot further back.
Ronan Rafferty, who won this event two years ago, was another Irishman well in contention, moving into joint-fifth place with a 66 for 135.
Steven Richardson, who is still searching for peak form, was on 136 but did not help his cause by losing a ball at the first hole, his 10th, when it sailed into the trees.
Cejka, who has a love of fast cars and owns a Ferrari, a Lancia and a Porsche, said he did not play to protect his lead. "I didn't want to screw it up with a 76 but I played aggressively," he said. "Today only four putts dropped while I had 11 single putts yesterday. That was the difference."
On current form he will be hard to catch, though both McGinley and Rafferty, anxious to seal a place in the Irish Dunhill Cup team which will be picked after the Czech Open next week, will not lack incentive.Reuse content