Paint factory fire lights up London sky

A paint factory is on fire in north-west London. Photo / Blake Ridder

Firefighters are tackling a massive fire at a North London paint factory, which witnesses is visible for miles around the city.

The London Fire Brigade advised locals living near the fire to avoid the area and keep their doors and windows shut while 15 fire engines and 90 firefighters fought the flames.

The call came in at 9.21pm (10.21am NZ time) and roads were closed around the factory, on Waterloo Rd, by London's North Circular.

Big fire now in Staples Corner in North West London. pic.twitter.com/xYnFxRW7Xk

— The Pileus #RefugeesWelcome (@thepileus) January 8, 2018

Massive Fire at Staples Corner in London pic.twitter.com/XD25YnF84C

— Shulem Stern (@ShulemStern) January 8, 2018

Avoid #staplescorner. @LondonFire are dealing with a serious fire. pic.twitter.com/uvKkPlKiVm

— Barnet MPS | North West BCU (@MPSBarnet) January 8, 2018

The London Fire Brigade tweeted it had received more than 45 emergency calls about the fire.

"This is a significant fire at a paint factory off the North Circular which can be seen across London. We'd ask people to avoid the area if possible and local residents to keep their doors and windows shut."

There are no reports of injuries.

Concerned passers-by have taken to social media to warn others of the blaze, which has been described as a "huge fireball in the sky".

One tweeted: "What on earth is this? Was just on the North Circular."

Another said: "Just passed the biggest fire I've ever seen in my life.

"Looks like a warehouse or something of that size near the North Circular at Wembley."

Another Twitter user posted: "HUGE fire off north circular just now. Literally exploding, plumes of smoke. I think it is a warehouse although not confirmed."