The major fire threat has been averted and it is safe for Blue Mountains residents to return to their homes, NSW Rural Fire Service Commissioner Shane Fitzsimmons said.

Mr Fitzsimmons said the high risk strategies of firefighters have paid off in extreme conditions on Wednesday.

He said residents who left the mountains earlier in the day can return in the early evening.

“It would be safe to head back home tonight because the risk has been averted,” he said.

Hundreds of Blue Mountains residents had fled their fire-threatened homes for evacuation centres outside the mountains.

Mr Fitzsimmons paid tribute to the emergency services and the community for heeding the advice of the RFS as fires flared up in the mountains and new blazes erupted in the Hunter region near Newcastle.

But he warned there was still a lot of difficult and dangerous firefighting being carried out.

Premier Barry O’Farrell lauded the “magnificent planning and preparation” which helped avert the worst on a day Mr Fitzsimmons had said would be “as bad as it gets”.