FIREFIGHTERS are scrambling to bring 14 fires in NSW under control as a total of 110 burn across state with today's temperatures to soar.

Total fire bans are in place for NSW, Victoria and the ACT today as authorities brace for temperatures in the low to mid-40s.

"We've obviously got severe fire danger," Deputy Rural Fire Service (RFS) Commissioner Rob Rogers said this morning.

"On the back of those very warm days the vegetation is very dry and all we need is sparks and we will have a fire going."

There are three main fronts of concern to authorities in NSW, with 90 firefighters still working to bring a blaze at Yass under control while the Deans Gap fire, also in the south near Sussex Inlet, continues to grow after destroying 8500ha.

There are 150 firefighters on site there while 50 of their peers battle a blaze at Cooma.

"We've still got 110 fires on our books, 14 of those uncontained, 350,000 hectares that have been burnt, those fires the principal concerns near Yass and down near Cooma, not contained," Comm Roger said.

"Under those conditions we're obviously concerned about those fires flaring up again as well as fires that we have contained and new fires that will start again."

More than 1000 firefighters are in the field today, and the dangerous weather front is forecast to hang around until tomorrow afternoon.

"We are braced for bad conditions, they are expected to be worse tomorrow and obviously we need to work on minimising the number of fires," Comm Roger said.

An RFS spokeswoman said strong winds forecast for today would exacerbate the threat.

"The focus is on getting as much containment as possible on the fires that are burning currently overnight," she told AAP.

"The fires, given they're already burning, they may well and truly go gangbusters."