This is the first in a series of papers on the Lecithoceridae (Lepidoptera, Gelechioidea) of New Guinea. Onnuria Park, n. gen. is proposed to accommodate three new species: Onnuria xanthochroa Park, n. sp., Onnuria melanotoma Park, n. sp., and Onnuria tenuiella Park, n. sp. The new genus shares with Pectinimura Park, 2008 and Neopectinimura Park, 2010 a similar specialized comblike plate on the valva in the male genitalia. It is differentiated from the aforementioned genera by the unique shape of the labial palpus with a very stout, strongly recurved 3^rd segment and highly specialized hind wing venation with M₃ and CuA₁ coincident and CuA₂ arising from before the middle of the cell. A key to the species of the genus is given. Adults, heads, labial palpi, hind wing venation, and male genitalia are illustrated.