Police officers have told their union, the Police Association, the Tennyson St station is at capacity, with toilets being used for locker rooms and limited space for the storage of exhibits.
Gear bags littered the hallways and were stuffed into any space available in the meal room.
The building is about 13-years-old.
“It is definitely not fit for purpose anymore and the sooner something else is developed the better,” Cahill said.
While no timeline for the extra building is known, it is understood when it arrives it could provide a dedicated training room, office space for an expanding youth aid and family harm team, space dedicated to the processing and storage of exhibits, and extra room for body armour systems and gear bags.
"Any approved option will be designed to help accommodate additional staff and support our operational needs in the area.
"Due diligence is ongoing, and we will be able to provide more detail once the agreed solution is approved," Hill said.
The temporary building will aim to fill the gap between now and the planned emergency service campus, tipped to go at the back of Helpet Park on Lincoln Rolleston Rd.
The campus would have a police station, fire station, ambulance station and space for civil defence emergency management, along with shared services.
Said Hill: "Police remain in engaged with the Selwyn District Council along with other emergency services about the potential development of the proposed emergency services hub in Rolleston.
"These conversations are still at an early stage, with business case approval, funding, and timelines yet to be established and finalised."
Cahill said if the campus does go ahead, it is unlikely any police would remain at Tennyson St.
The association also reported police have completed work at the Lincoln police station to repair leaks and fix mould issues in the roof and internal walls, while rotten posts have been remedied in the foyer of the Darfield police station.
