The family of a Christchurch woman who was last seen almost three weeks ago say they are concerned for her well-being.

Police are appealing for sightings of Scarlett, who has been reported missing and was last seen on Friday, July 31, in Riccarton.

"Police and Scarlett's family are concerned for her well-being and would like to find her.

“If you see Scarlett, please call 111 and reference file number 260803/6648. If you have information that could be helpful, please visit 105.police.govt.nz, click ‘update report’ or call 105.”

You can also make an anonymous report to police via Crime Stoppers — 0800 555 111.