More than 150 firefighters were in the early hours of Monday morning battling a bushfire that had destroyed dozens of properties near Bega on the New South Wales south coast.

Key points: A bushfire is out of control in Tarraganda and Tathra, near Bega

A bushfire is out of control in Tarraganda and Tathra, near Bega A number of homes in Tathra are believed to have been damaged or destroyed by the fire

A number of homes in Tathra are believed to have been damaged or destroyed by the fire Some Tathra locals are being evacuated to Bega

The blaze, which impacted Tathra and Tarraganda, had crossed the Bega River at about 4:00pm AEDT on Sunday.

At 1:00am AEDT on Monday the fire remained out of control, and a watch and act warning — which had been downgraded from an emergency warning — was in place for the Bega Valley.

Advice warnings were in place for a number of other fires in the state.

A southerly change hit the area near Bega late on Sunday night and conditions began to ease, but authorities warned residents to continue monitoring the situation and be prepared to enact their bushfire survival plan should the blaze become a threat again.

Paul Best from the NSW Rural Fire Service described it as "a potentially volatile situation".

He said authorities would not know the full extent of the damage until later on Monday.

"Bush fire impact assessment teams will move across the fire ground today, and undertake those assessments of properties that have been destroyed or damaged. So that will occur throughout today," Mr Best said.

Up to four people had been hospitalised with smoke inhalation by late Sunday evening, according NSW Family and Community Services.

One firefighter has been treated for a minor injury.

Flames come close to a home in Tathra. ( ABC News: Peta Doherty )

The NSW RFS Deputy Commissioner Rob Rogers said the blaze had "burnt some seven kilometres right into Tathra itself, unfortunately impacting a lot of homes in the area".

"I think we'll hear in days to come some of the dramatic experiences people have had this afternoon," he said.

"I think it's been a pretty horrendous time for both firefighters and residents in that township this afternoon.

Power and communication lines are still being restored in the town. ( ABC News: Peta Doherty )

Power outages caused by the fire have affected hundreds of homes in Tathra and the surrounding areas.

While the RFS had warned it was too dangerous for Tathra locals to leave the area, some residents were evacuated to Bega.

An evacuation centre was established at the Bega Showground and animals were being accepted.

A number of schools will be closed on Monday in the Bega and Tathra area.

Flames can be seen from an out-of-control bushfire near Tathra. ( Twitter: Paul Tyquin )

Total fire bans were declared in 11 areas around NSW on Sunday.

The RFS said it had been a dangerous and difficult day in the state, with 26 bush and grass fires burning, 12 of which had been uncontained.