Dendrobium cuthbertsonii is widely distributed on the island of New Guinea from the northwestern part of Irian Jaya along the central dividing mountain range down to the southeast of Papua New Guinea, on the mountains of the Milne Bay Province. This species has also been sighted on Goodenough Island and the southeastern mountains of New Ireland. The species appears to prefer an environment that encounters frequent rain, although the rain does not need to be daily of heavy. On the mountain slopes leading to the Tari Gap temperatures during the day may rise as high as 25 o Celsius. There is constant air movement along the mountain ridges, and at higher altitudes strong winds prevail throughout most of the day.
Humidity is quite low.
Apart from the outstanding flower colours the most intriguing characteristic of the species are the 'warty' leaves and ovaries. The purpose of these 'warts' is unclear but it is assumed that they serve as water traps. There is no other orchid known anywhere with a similar leaf epidermis. The flowers appear 'upside down' with the labellum being the uppermost part of the flower. Along the road from the Ambua Lodge to the Tari Gap one can clearly observe the terrestrial habit of the species.