The joint exhibition - ''A Moment in Time'' - incorporates images from the past and present, which are represented by a path, character or memorable moment from the women's lives.
Included will be a piece by Errington, with a retail value of $3250, which will be sold by a silent auction that will run until May 29.
Proceeds over the reserve price will be given to Cure Kids, a charity which funds research into life-threatening diseases that affect children.
The painting, titled The Peaceful Place, was inspired by a pair of tuis living in Errington's garden, and features several native New Zealand birds in and around a beech tree.
''People might have an emotional connection to it - it's something New Zealanders can relate to.''
The exhibition will also include Butler's published character, ''Ruby'', along with new portraits featuring vibrant colour and ''creatures'' to emphasise an emotion.
''I've always loved painting and drawing and colour is a passion of mine. After graduating with a first-class honours degree in textiles, I made the decision to make my passion my job and I'm still doing it, continually exploring narrative in my work,'' she said.
Errington's award-winning ''Light Changing'' series would have a new twist, introducing whimsical characters or paths based on shadows of the past and reflecting the history of the local landscape.
Her style of sculptured, textured trees created depth to allow the viewer to believe they were almost part of the painting.
''I mainly work with acrylics and modelling compound.
''I combine them on the same painting to create texture.''
• A Moment in Time opens to the public on Friday and runs at Artbay Gallery until May 29, from 11am-5pm. Bids for the silent auction can be made at the gallery, or at www.artbay.co.nz.