A man died in a fire in a block of flats in Invercargill early Wednesday.

Neighbours have described being woken by screams in the street as a block of flats went up in flames.

One man is dead after a fire almost wiped out a block of flats in Invercargill overnight.

Emergency services were called to the block of five flats in Tramway Rd about 1.10am on Wednesday.

DAVE NICOLL/FAIRFAX NZ Two of the flats in the block on Tramway Rd were well ablaze when firefighters arrived.

A female resident in the block of flats posted on Facebook early Wednesday morning.

"OK i so sad and still in shock right now. My flat and my two neighbours on each side of me went up in flames. My friend of 40years died instantly ... Love u my friend."(sic)

Neighbour Tristan Rea who lived opposite the flats said he was woken up by screams outside the flats some time after 1am.

DAVE NICOLL/FAIRFAX NZ The fire spread considerably through the block of flats and took quite an effort to extinguish.

He had just gone to bed when he was woken by the yelling and screaming and looked out his window to see the flats across the road on fire.

His brother Chris had friends who lived in the flat so he ran out of the house and across the road to try and help, Rea said.

"He ran out there trying to do anything but the flames were too massive."

RADIO NEW ZEALAND A person has been found dead after a fire in a block of flats in Invercargill. The fire broke out just after 1am.

At the time firefighters had not arrived so Rea called emergency services.

The fire spread in a matter of minutes, Rea said.

His brother's friend Monique Bostock lived in the flat which had caught fire with her friend Julie Tahuhu.

Tahuhu managed to escape the flat but feared for Bostock who she believed was still inside, Rea said.

Tahuhu was crying and screaming in the street.

Bostock was woken by her dog and managed to escape the fire by going through the bathroom window out the back of the flats, Rea said.

"Lucky she had her dog otherwise she wouldn't be here.

"She's safe so that's the main thing."

Someone else was in the flat with them but Rea did not know who it was, he said.

Bostock, Tahuhu and the others from the flat were being looked after by victim support now, Rea said.

Another neighbour said he was woken by what he thought was a disturbance on the street.

When he looked out of his window, he saw the middle flat across the road well ablaze and called emergency services, the neighbour said.

There were at least half a dozen onlookers outside on the street, he said.

The firefighters arrived within minutes after his call, the neighbour said.

Fire Service Southland assistant area commander Deane Chalmers said two of the flats were well ablaze when firefighters arrived.

The crews found a man dead within one of the flats.

The fire spread considerably through the block of flats and took quite an effort to extinguish, Chalmers said.

"It burned quite well through the roofing structure of the building. In order to extinguish it fully, the guys had to do a lot of work to remove roofing iron to get at the fire."

Two crews were left at the site dampening down hot spots by 5am.

The cause was not yet known, Chalmers said.

Police were involved and fire investigators would examine the scene.

In a statement, police said they were in the process of identifying the man and finding his next of kin.

"Victim Support is working with those displaced by the fire," they said.