Originally an order for Philippine National Railways 2500 Class, the six locomotives were purchased as by coincidence NZR needed a heavy shunter for Auckland container port transfer work. At the time two DSC class shunters were linked in tandem to perform this task. The DH class are actually a light locomotive which are geared to run at 100 km/h (62 mph). They saw occasional service on the then under-used suburban passenger network, performing well, but NZR focused them on their intended purpose - heavy shunting. In the late 1980s NZR provided a DH unit to the Tasman Pulp and Paper mill in Kawerau to trial for sale as a heavy shunter in the mill's rail yards. The mill turned down the offer, instead purchasing a DA class locomotive to perform duties.