The NSW Rural Fire Service has warned this year's bushfire season will be worse than last year, when more than 200 homes were lost in the Blue Mountains.

"Without being alarmist in any way, we are being realistic based on the forecast and the underlying conditions that this season is shaping up to be a difficult one and on the forecast alone, more problematic than last year," NSW RFS commissioner Shane Fitzsimmons said.

The official fire danger period for New South Wales starts tomorrow, but the bushfire season began early for areas of Sydney due to a predicated forecast of dry conditions.

Above-average temperatures and below-average rainfall over the next three months would be contributing factors to the high level of danger, Mr Fitzsimmons said.

Hot and dry conditions were expected to prevail with a risk the condition could be intensified by an El Nino event.

Emergency Services Minister Stuart Ayres said householders need to have a bushfire survival plan in place now and warned against complacency due to recent rain.

"The weather conditions are not going to be our friend over the course of this period," Mr Ayres said.

"We will see hot, dry and windy conditions. This will lead to conditions where fire is extremely high risk.

"In fact over one million properties will be at risk throughout the course of this season."

Mr Fitzsimmons said research undertaken in bushfire devastated areas last year revealed one in four people did not have a bushfire plan in place.

He said the mentalities of "she'll be right mate, it won't happen to me", were preventing all householders from being fully prepared.

"I don't know how many years I've got to keep saying it, it's not good enough when it comes to bushfires," Mr Fitzsimmons said.

"People need to accept that risk, they need to do something about that risk.

"We will do all that we can, but it will make all the difference if individuals do what they can."

Mr Fitzsimmons urged people to develop a bushfire plan now and have their homes fire-safe ready for the season.