It is endemic to Sudest Island, a part of Louisiade Archipelago in the Milne Bay Province of Papua New Guinea.

[2] The specific name axanthogaster is derived from Greek words meaning "without yellow belly", which distinguishes it from its close relative M. louisiadensis with which it was formerly included.

Dorsal skin has faint, scattered dermal pustules; the flanks as well as the belly are smooth.

[1] Mantophryne axanthogaster occurs at elevations of 100–800 m (330–2,620 ft) above sea level, ranging from primary lowland rainforest cloud forest.

Males call from exposed sites on the ground, often near small piles of leaf litter.