Tathra residents were extremely unlucky strong winds pushed a bushfire into the heart of their township, destroying almost 100 homes, cabins and caravans on the NSW south coast.

Five fires initially started around Bega on Sunday in “extraordinary” conditions with wind gusts up to 90 km/h, Rural Fire Service commissioner Shane Fitzsimmons says.

The main fire spread in an elongated fashion “straight towards the ocean”.

“If the fire was a few hundred metres further north or a few hundred metres further south it would have likely gone right past Tathra,” Mr Fitzsimmons said in Bega on Monday.

“But sadly the direction the winds blew this fire put it right into the centre of the township.”

Fire crews on Monday afternoon confirmed 69 houses and 30 caravans or cabins were destroyed. A further 39 houses were damaged with nearly 400 saved.

Prime Minister Malcolm Turnbull was shocked at the destruction.

“Thank heaven there have been no lives lost,” he told reporters during a visit to the Bega evacuation centre.

“That’s a great tribute to the community, to the firefighters, to all of that preparation and resilience.”

Residents are anxious to get back into the township to assess their homes.

But before that can happen, authorities need to make the environment safe “as quickly and practically as we can,” the RFS commissioner said.

Power, utilities and communications need to be fixed and there’s the possibility of asbestos “floating around”.

Also causing access problems is the main road between Bega and Tathra being used as a control line to fight the blaze which remains uncontained.

Premier Gladys Berejiklian defended the manner in which locals were warned of the impending inferno.

Warnings were delivered via mobiles and also landline phone calls.

Emergency warnings were very targeted, with some people told to stay and others advised to evacuate, she said in Bega.

“Because of the location, mobile phone reception is not always possible and I understand very early on some of the phone towers were damaged themselves.

“Communication was a challenge, but I’m absolutely confident we did everything we could as quickly as possible to get the message out.”

Authorities “talked for 24 hours or more” about the risks due to the extreme weather conditions, Mr Fitzsimmons said, and there were total fire bans across two-thirds of the state.

The RFS website was also regularly updated.

“The teams have done a pretty extraordinary job given the circumstances that were confronting them,” he said.

“Our primary focus must always be the preservation of life and at this stage … something worked to keep everybody alive in what could otherwise have been a more horrendous situation.”

Two firefighters suffered heat exhaustion while a woman in her 40s suffered minor burn injuries.

Crews are still trying to contain the fire on Monday afternoon. Weather conditions are more favourable and there could be showers on Tuesday which will help firefighters.

The township has been officially declared a disaster area. Euan Ferguson has been appointed coordinator-general to oversee the recovery operation.

The Insurance Council of Australia has declared the fire a “catastrophe”, meaning claims by those affected by the blaze will be given priority.

Several schools in Tathra and Bega were saved but remain closed.

There are 19 fires burning across NSW with 12 uncontained.