A woman has been arrested and a firearm seized after a Facebook Marketplace deal in West Auckland went wrong.

Shortly after 1am on Tuesday, the victim met a person in Westgate as part of a purchase through the platform, Waitematā West area response manager Senior Sergeant Damian Albert said.

The victim then got into the offenders’ vehicle, where his phone and ATM card were allegedly stolen.

“An amount of cash was withdrawn from the victim’s account before the two offenders fled the area in two separate vehicles,” Albert said.

“Police were provided with detailed descriptions of both vehicles, with one quickly located travelling through Manurewa.”

Police stopped the vehicle on Landette Rd and located two female occupants. A search of the vehicle uncovered a modified pistol, ammunition, cannabis and stolen property.

A 25-year-old woman is set to appear in the Waitākere District Court charged with theft, unlawful possession of a firearm and possession of cannabis.

“Police are committed to identifying and holding offenders, who choose to put the safety of others in jeopardy, to account,” Albert said.

“This was great work carried out by our staff to swiftly identify and apprehend those responsible for this incident.

“We are pleased to see one less firearm on our streets, and we will continue our work to disrupt unlawful activity in an effort to help our community feel and be safe.”

Albert said inquiries into the incident remain ongoing.