Airbnb

CEO Brian Chesky said in a tweet the company would take steps to "combat unauthorized parties and get rid of abusive host and guest conduct".

"We must do better, and we will. This is unacceptable," Mr Chesky added.

Three people died at the house, in the city of Orinda, near San Francisco, and two more died later in hospital.

The American woman, who asked to remain anonymous, described her husband's affair with their Auckland host as a "twisted form of internet dating" which has ended their marriage of 30 years.

In autumn last year the woman and her husband visited Auckland, choosing an Airbnb host for the space and facilities it offered over a hotel. She could not have imagined the consequences of that decision.