Searchers have been scouring areas of interest for missing Christchurch woman Yanfei Bao.

The real estate agent was last seen in Wigram last Wednesday, and police are now treating the disappearance as a homicide investigation.

Efforts are focused on the Halswell River, Greenpark, Lake Terrace Road and near New Brighton and Palmers Road intersection.

NZ Herald senior crime reporter Sam Sherwood says the duration of the investigation and new discoveries coming to light have caused police to launch a homicide investigation.

"As the week has progressed, and in particular, the last couple of days, more information has come to light- which is now why they've launched a homicide investigation." 

LISTEN ABOVE

• Missing Yanfei Bao: Police searching stretch of Halswell River
• Senior crime journalist explains police are treating Yanfei Bao as a disappearance
• 'I do not believe she is alive': Cops launch homicide probe in search for Yanfei Bao
• Missing real estate agent: Police charge man with kidnapping