Routine astacological surveys in northeastern New South Wales have revealed four new species of crayfish. Three species are allied to the "setosus complex", a group of small and poorly spinose Euastacus previously recorded only from Queensland: E. girurmulayn n.sp. from the Nightcap Range, E. guruhgi n.sp. from the Tweed volcanic plug and E. jagabar n.sp. from the Border Ranges. These three species are differentiated chiefly on features of the sternal keel, spination and antennal squame. Euastacus dalagarbe n.sp., recorded from the Border Ranges, has affinities with a growing group of crayfish displaying morphological traits intermediary between the setosus complex and more characteristically spinose Euastacus. It differs markedly in spination of the chelae, and in the nature of the lateral processes of the pereiopods. All of these taxa occur in association with the much larger and more spinose E. sulcatus. An unusual crayfish specimen of uncertain status is also discussed.