Cerius otagensis is a species of flightless fungus weevil that is endemic to New Zealand.

[3] Only four female specimens have ever been collected and the male of the species remains unknown.

The species was discovered by J. S. Dugdale on 25 November 1974 at Gentle Annie Creek, Kawarau Gorge.

On 27 October 1981 a fourth specimen was collected by J. C. Watt 4 kilometres (2.5 mi) north of Lindis Crossing as a result of beating Carmichaelia petriei.

A. Holloway and the holotype specimen is held in the New Zealand Arthropod Collection at Landcare Research.