Electricity and communication blackouts on Wednesday continued to challenge authorities and many thousands of visitors were stranded in towns from Nowra all the way south to the Victorian border.

However, the restoration of power in some areas, including Ulladulla, allowed stranded motorists to refuel ahead of anticipated partial reopening of the Princes Highway from Batemans Bay north towards Nowra.

The NSW Rural Fire Service has urged tourists between Batemans Bay and the Victorian border to leave the coast before Saturday, January 4 when extreme fire conditions similar to New Year's Eve are predicted. Those planning to visit the South Coast this weekend have been warned to stay away.

NSW Rural Fire Service Commissioner Shane Fitzsimmons said the partial or full reopening of key roads, including Snowy Mountains Highway, which connects Canberra to the coast via Cooma, presented an opportunity for people in many areas of the South Coast to leave ahead of Saturday's forecast extreme conditions.

"Our message is as soon as the roads are able to be traversed, we are encouraging, particularly holidaymakers and visitors to the south east of the state, to make their way out of the south east of the state to safer places," Mr Fitzsimmons said.

A statement by NSW Rural Fire Service Far South Coast and the Eurobodalla Council said pressures on the southern shire would be eased if visitors left while they could.

"We urge visitors to leave Eurobodalla via Narooma as soon as possible. It is in their best interests and the best interests of our community," it said.

"Only leave now if you have enough fuel to get to Cooma. We will advise as soon as fuel is available in Narooma and Moruya."

George Bass Drive, the coast route from Moruya to Batemans Bay, was closed in parts for trees to be cleared from the road. There was access from Moruya to Broulee and Tomakin, and from Batemans Bay to Malua Bay.

The road was scheduled to be completely clear by Friday.

NSW Police Deputy Commissioner Gary Worboys said access out of the Shoalhaven via the Princes Highway was being allowed under police, RFS or traffic operations control.

"We really want people to make sure that they abide by the directions that they are giving, and understand that this piece of roadway is still quite vulnerable in terms of the active fire space and we will continue to progress people moving up and down that road this afternoon, into tonight, where that is possible, and certainly through tomorrow as daylight comes," Deputy Commissioner Worboys said on Wednesday.

"South of Batemans Bay, we will also work with that with some local roads down the coast that will bring people down in through Bega, Bermagui and across Brown Mountain, into Cooma, Canberra, and they can make their way then up towards Goulburn, up the Hume towards Sydney and out further west."

Deputy Commissioner Worboys said anyone thinking of coming to the coast for planned holidays should not do so.

"It is something that we need to make sure that people do not intend to travel there in the next few days, and those people that are there that need to get out, need to make sure they make good decisions, that they are ready to go and that they travel safely out of the South Coast."

With coast residents and visitors cut off by road and without landlines and computers, communication has been difficult.

Most businesses were closed, with long queues for a Batemans Bay supermarket and for fuel, but with electronic payment down people were struggling to find cash to pay for fuel.

The chaos was hampering efforts to evacuate areas that were accessible by road as people tried to return to Canberra and elsewhere.

Commissioner Fitzsimmons said authorities were focused on getting power restored to petrol stations to get pumps operating, and getting food and supplies to people.

"The three big issues are power, communications and fuel. They're interconnected," he said.