Crimson and Eastern Rosellas are hollow nesters and will use nesting boxes in domestic gardens. Indian Mynas may also compete with rosellas for these nesting sites, so householders need to be vigilant and remove any mynas / eggs that occupy the box.
The dimensions for a simple nesting box for rosellas are:
Sides: 400mm deep x 230mm wide x 4 sides
Bottom: 260mm x 230mm
Top: 360mm x 300mm
Entrance hole: 65mm
Piano hinge or other hinge: either the top or bottom or both can be hinged. A hinged bottom allows for ease of removal of mynas nests. A hinged top enables the householder to observe what is in the nest (this should only be done if there is any doubt as to whether myna or rosella chicks are in the nest).
See photos of completed box and the pieces: