Elisabeth, 79, was last seen on Bartlett St in Riccarton about 6pm on Wednesday June 4.
She was wearing blue pants, a dark coloured long-sleeve top, black shoes and has distinctive long blond/white hair.
Senior Sergeant Todd Webley said police hold serious concerns for her well-being.
"We have a large number of staff on the ground, including from Land Search and Rescue, but we really need people in the Riccarton and surrounding areas to check home security cameras, and also around their properties, in sheds and garages, in case Elisabeth is there.
"Area searches have been carried out through Riccarton, nearby high schools, sport fields and retirement homes, and on both sides of the Avon River from the Botanical Gardens traffic bridge, and Hagley Park.
"This is a significant search, but we need the public’s help to locate Elisabeth as soon as possible.
"We know people are finishing work for the day, and the best way they can assist us is to check their properties and call 111 if they find her.”
Webley said search teams would remain on the ground into the evening "if it comes to it".
Elisabeth’s family were also being provided updates on the search.
"It is getting cold, and everyone on the ground is focused on bringing Elisabeth home as soon as possible."
Anyone who sees Elisabeth should ring 111 immediately and use the reference number 250604/5465. Non-urgent information can be provided online at 105.police.govt.nz, using “Update Report”, and quoting the same reference number.
- APL
