One person has been seriously injured and another has moderate injuries after an assault in Lyttelton tonight.

A police spokeswoman told Chris Lynch at 745pm police received a report of an assault at a residence in St Davids Street.

Chris Lynch Media understands a stabbing took place.

The police spokeswoman said one person was taken in to custody and two people are being treated, one of them for serious injuries, one of them for moderate injuries.

The people involved in the incident are known to each other.

Five ambulances were at the scene on St Davids Street.

Police officers were talking to neighbours outside a two story house, while several officers were seen inside the house on the second floor examining the property.

A witness said they saw a woman was being assisted into an ambulance by staff with a towel wrapped around her head.

Police have cordoned off the house involved in the incident.

Police units are also parked in the middle of Exeter Street and on Oxford Street.