Some Alexandra residents watching helplessly as their homes go up in flames. Picture: @Alexfm891 Twitter

An alleged revenge attack stemming from a love triangle is believed to have led to hundreds of people losing their home when a man set his rival's shack on fire.

The fire then spread and destroyed over 500 structured.

This was according to a man who called on Radio 702's Aubrey Masango's show on Thursday night following the devastating blaze.

The man said the story he heard was that two men were fighting over a woman and then in a fit of anger, one of the men set the other's shack on fire.

Spokeswoman for the Johannesburg Emergency Services Nana Radebe said all that they heard was that there had been a fight and that a man had set another's shack on fire.

However, she could not confirm the love triangle claim.

Shocked residents returned from work to find their homes and belongings burnt to ashes.

The fire department battled to put out the flames in the area owing to the lack of fire hydrants.

Radebe said it was difficult to contain the raging flames in such conditions.

“There are no hydrants here because people built on top of them. It is now making the job of the firefighters difficult,” she said.

Scores of families were left homeless, with some scrambling to save their belongings.

It’s not clear what started the inferno, which began at the corner of London Road and 18th Avenue. No fatalities and injuries were reported.

Radebe urged those wanting to assist to drop off food and clothes at the Sandton and Alexandra fire stations.

Many of the pictures and videos circulating on social media show despondent Alex residents, watching on helplessly as their homes go up in flames.