Dramatic footage has captured a massive fire engulfing a commercial building in Sydenham, sending towering clouds of black smoke across Christchurch.

Emergency services were called to the blaze on Brisbane Street about 11.30am on Wednesday.

Seven Fire and Emergency crews are battling the flames, with aerial ladder trucks being used to attack the fire from above.

Fire and Emergency confirmed the single storey building, measuring approximately 40 metres by 20 metres, was fully involved in fire.

All people have been accounted for.

The building has suffered extensive damage, with firefighters working to prevent the flames spreading to neighbouring premises.

Strong winds have been fanning the blaze, sending significant amounts of smoke towards Moorhouse Avenue.

Police have closed roads around the scene, including the intersections of Brisbane and Byron streets and Gasson and Carlyle streets.

Traffic has backed up for several blocks, while dozens of onlookers have gathered to watch the emergency response.

Fire and Emergency is urging people to avoid the area and keep doors and windows closed because of the smoke.

 

Anyone with health concerns can contact Healthline on 0800 611 116.

The cause of the fire remains unknown, and there has been no confirmation of injuries.