A man has been seriously injured after he fell three metres from a ladder at a property in the area of a massive bushfire on the NSW mid-north coast.

Aged in his 70s, the man suffered chest and abdominal injuries in the fall at a property on Hillville Rd, Hillville about 4.45pm on Saturday, NSW Ambulance said.

The road was the starting point of a bushfire that has burned nearly 30,000 hectares south of Taree over the past fortnight.

AAP

Westpac Rescue Helicopter Service said the man may have been cleaning his gutters to protect his property from fires.

He was flown to John Hunter Hospital in a serious-but-stable condition.

In Sydney's northwestern outskirts firefighters are still battling a large blaze

NSW Rural Fire Service Inspector Ben Shepherd says the fire, which has been downgraded to a "watch and act" alert, is unlikely to be under control before weather conditions deteriorate early next week.

The fire had destroyed six homes since catastrophic conditions were declared on Tuesday, with one more home possibly lost on Friday, Insp Shepherd said.

"The fire itself has now burnt out more than 100,000 hectares and it has destroyed six homes," he told AAP on Saturday morning.

"We've had reports that one further home may have been lost yesterday. Building assessment teams will look at that today.

READ MORE This man's act of kindness towards a koala injured by bushfires has gone global

"It's unlikely we'll have it contained before more dangerous conditions come."

A southerly change sweeping through the state eased the Gospers Mountain fire on Friday night, allowing firefighters to strengthen containment lines through back burning.

This work would continue on Saturday as long as it was safe, Insp Shepherd said.

The biggest danger moves to the north of the state on Saturday - with severe ratings issued for New England, the Northern Slopes and northwestern regions.

Total fire bans are in effect in those areas, as well as the far north coast, on a day that will have temperatures moving into the mid-30s, very low humidity and gusty winds once again.

"It's a little bit like groundhog day," Insp Shepherd said.

"Once again we've got severe fire dangers and such a huge area of fire that we are dealing with.

"As conditions worsen this afternoon we could see properties threatened. Communities need to remain vigilant."

AAP

Bureau of Meteorology duty forecaster Bimal KC says a southerly change will bring some brief relief on Saturday before fire conditions worsen early next week.

"The temperatures we are expecting are a little bit lower as the southerly change comes through," he told AAP on Saturday morning.

"On Sunday we are expecting similar conditions. Later on Tuesday the conditions will get worse as the heat starts building up.

"Tuesday and Wednesday will be fire weather days, with the weather conditions again deteriorating."

Five out of control fires were burning at a watch and act level on Saturday morning.

These fires were in Woodenbong, Willi Willi, Nambucca, Bora Ridge as well as the Gospers Mountain blaze.

AAP

The RFS said more than 150 brigades will open on Saturday morning to speak with residents across the state about their fire plans at the beginning of what is expected to be a long bushfire season.

"We are encouraging everyone to use this weekend to prepare," Insp Shepherd said.

"A number of brigades are throwing open their doors so people can go in and discuss their levels of preparation."

The four people killed in bushfires over the past week are Barry Parsons, 58, at Julie Fletcher, 63, Vivian Chaplain, 69, and George Nole.

A man suspected of starting a blaze which sparked an emergency warning at Guyra Road in Ebor, east of Armidale, was arrested on Friday and was refused bail to appear at Armidale Local Court on Saturday.