A smell emanating from a stormwater drain on Chadwick Road caused confusion resulting in the evacuation of the Department of Conservation building today.

Staff were evacuated from the building on the corner of Chadwick Road and Hayes Avenue around 9.35am after emergency services received a call to a gas leak at the Greerton site.

Department of Conservation staff were evacuated from the building.

It was originally thought to be a leak in the basement of the building.

Northern Fire communications shift manager Dallas Ramsey says an ambulance was called to the scene to treat a person who had become sick from the smell.

She says no action was taken by the brigade and people returned to work once the confusion was cleared up.