The 12,500-dwt units are due from Jiangzhou Shipyard in China in November 2015 and January 2016, German media reported.
The vessels are costing $18.5m each, with two more options attached.
They will come with two Liebherr cranes and consume a quarter less fuel, allowing the company to save $3,000 per day
Auerbach already operates three MPPs.
