POLICE have charged a woman who allegedly held her own grandmother under siege with a knife in Southport overnight.

Around 9.30pm, police declared an emergency situation under the Public Safety Preservation Act after reports that a woman in her 60s was being held in a house on Cotlew Street by a woman armed with a knife.

Police negotiated with the woman throughout the night, and was taken into custody around 4am.

A 61-year-old woman was taken to hospital for treatment for what are believed to be minor injuries.

A 17-year-old Southport woman has been charged with one count each of serious assault of a person over 60, assault occasioning bodily harm and deprivation of liberty and torture.

She is due to appear in the Southport Magistrates Court on Friday afternoon.

Grandmother held hostage for eight hours in home

AFTER eight hours, an armed teenager has released her grandmother and ended a marathon siege on the Gold Coast.

The 17-year-old woman barricaded herself and her grandmother inside a Southport home on Thursday night.

At 9.30pm, police declared an emergency situation.

She was armed with a knife.

Police negotiators were eventually able to calm the situation, with the teen leaving the home and being taken into police custody.

At 4am, specialist officers entered the house and took the woman into custody "without incident".

Almost an hour later, the emergency declaration was cancelled.

Police confirmed the grandmother is "safe and well with some minor injuries".

She is being taken to hospital for treatment.