Bamber, Formula One driver Nico Hlkenberg (Germany) and Nick Tandy (Great Britain), who were entered for the first time, started second but lost ground because of an accident which was followed by a stop for repairs. They recovered after dropping to the back of the field, to finish sixth.
Tandy started second and was third after lap one. On lap seven, a misunderstanding led to an accident with one of the works Porsche 911 RSRs, and required a stop for repairs. After 32 laps, Hlkenberg took over the car in ninth position for a double stint. After 80 laps, Bamber got behind the wheel for the first time. He refuelled after 104 laps and handed over after 128 laps to Tandy, who picked up fresh tyres for the left-hand side at his last stop for fuel after 152 laps.
"We tried to fight back after we dropped down the order, and we ended up in sixth, 24-year-old Bamber said.
"For us it is most important to get ready for Le Mans next month and the experience in traffic is part of it. I'm used to traffic from the US racing, but the new element is the speed and having to overtake all the time. The car was handling very well and I enjoyed it a lot."
A one-hour highlights package of the six-hour race will screen free-to-air in New Zealand on TV3's CRC Motorsport programme on Sunday.