The yellow-bellied flyrobin (Cryptomicroeca flaviventris ) is a species of passerine bird in the Australasian robin family Petroicidae. It is the only species in the genus Cryptomicroeca. The yellow-bellied flyrobin is endemic to New Caledonia, where it occurs on the island of Grande Terre. It occupies a range of habitats, including dry lowlands, woodland, Pinus and Pandanus forest, and humid forest from sea level up to 1,525 m (5,003 ft).
The yellow-bellied robin is a medium-sized Australasian robin, 14–15 cm (5.5–5.9 in) in length and weighing around 12 g (0.42 oz). The plumage is similar to members of the genus Eopsaltria : dark olive-grey back, tail and wings, grey head and chest with a slightly lighter throat, and yellow belly and rump. The legs are grey.