The Utiku landslide in the central part of North Island, New Zealand, is a composite failure in Pliocene siltstones, part of a regional east-northeast-trending sedimentary belt across the entire island. The Utiku slide, a small portion of a larger, ancient landslide complex, was reactivated in 1964 and has caused considerable damage to the North Island Main Trunk railway line and State Highway 1, both major transportation routes between Wellington and Auckland.

The Utiku landslide is unique in that movement is almost parallel to the strike of the underlying siltstone. The lower, planar slip surface is a thin montmorillonite layer, and the principal driving force in the upper part of the slide is believed to be primarily from seepage forces developed in wide tension cracks.

Several different stabilization measures are possible to reduce or eliminate movement. Although some remedial measures have been attempted and others have been recommended, the landslide continues to move, and eventually a larger portion of the ancient slide may be reactivated.