They are understood to form a distinct lineage within the passerines, but authorities differ on their assignment to the oscines or suboscines (the two suborders that between them make up the Passeriformes).

They form monogamous pair bonds to raise their young, laying their eggs in small nests in trees or amongst rocks.

In the 1880s, Forbes assigned the New Zealand wrens to the suboscines related to the cotingas and the pittas (and gave the family the name Xenicidae).

As no evidence indicates passerines were flightless when they arrived on New Zealand (that apomorphy is extremely rare and unevenly distributed in Passeriformes), they are not required by present theories to have been distinct in the Mesozoic.

Plate tectonics indicate that the shortest distance between New Zealand and those two continents was roughly 1,500 km (930 mi) at that time.

The extant species are closely related and thought to be descendants of birds that survived a genetic bottleneck caused by the marine transgression during the Oligocene, when most of New Zealand was under water.

Both the New Zealand rock wren and the rifleman also show sexual dimorphism in size; unusually for passerines, the female is larger than the male.

The New Zealand wrens evolved in the absence of mammals for many millions of years and the family was losing the ability to fly.

The skeletons of these species have massively reduced keels in the sternum and the flight feathers of Lyall's wren also indicate flightlessness.

Contemporary accounts of the Lyall's wrens on Stephens Island describe the species as scurrying on the ground rather than flying.

Prior to the arrival of humans in New Zealand (about 1280 CE), they had a widespread distribution across both the North and South Islands and on Stewart Island/Rakiura.

The situation with the New Zealand rock wren is an ornithological mystery, as they are thought to live above the snow line where obtaining food during the winter would be extremely difficult.

They may enter a state of torpor (like the hummingbirds of the Americas or a number of Australian passerines) during at least part of the winter, but this has not yet been proved.