Teams were now carrying out an urban search in and around Karori, Mr Harmer said.
"We appeal to anyone in the Karori area who may have seen Mae since yesterday morning and come forward and contact police."
Mrs Cairns is described as having an extremely small build. She was believed to be wearing a white top, blue jeans and black shoes.
Police are urging people in the wider Karori area to check their properties and to get in touch if they have seen Mrs Cairns during the past 24 hours.
Mr Harmer said police were grateful for offers of assistance from various members of the Karori community, but extra help was not needed at this stage.
Police last night distributed a "large number" of fliers and posters, and would distribute more today.