The NSW bushfire crisis has people "living in fear" with more than 100 blazes burning across the state and Sydney choking on harmful smoke pollution.
Firefighters will have a brief window over the weekend to get on top of the crisis before the weather deteriorates early next week.
The Bureau of Meteorology has painted a grim picture for the coming week, with winds forecast to whip dangerous fire grounds and no rain relief in sight.
At one point on Friday there were nine fires burning at an emergency level, including the massive Gospers Mountain blaze, which has merged with neighbouring fire grounds to create a "megafire".
Smoke from the fires was drifting to New Zealand and affecting communities there, NSW Rural Fire Service commissioner Shane Fitzsimmons said on Friday.
There were 108 fires burning in NSW on Friday afternoon, with 74 of those burning out of control.
Hazardous air pollution readings were recorded in many parts of the state, with emergency departments seeing an increase in presentations for respiratory issues.
Six people have died so far this fire season while more than 680 homes have been lost.
A couple preparing to defend their property from the Gospers Mountain fire burning northwest of Sydney say conditions are unlike anything they've seen before.
Martin and Karen Waterman have spent the past few weeks preparing to defend their Karingal Equestrian Centre at Mangrove Mountain, where they live with 22 horses.
"We haven't had these circumstances ever that I know of," Ms Waterman told AAP on Friday.
Hawkesbury City Council deputy mayor Mary Lyons-Buckett says the blazes can only be described as a "megafire".
RFS deputy commissioner Rob Rogers says firefighters are concerned about the Gospers Mountain fire pushing into Gosford.
"The best thing we can do is try and protect property and people as much as we can and that's what our mission is today."
NSW Premier Gladys Berejiklian says residents from the South Coast up the Queensland border are "living in fear".
"The difference now as we lead into the summer months is previously they (bushfires) were pretty much confined to the northern part of NSW but what we are seeing this week is our resources stretched across the entire coastline," she told reporters.
"Our thoughts are with the people who have been displaced and people who are living in fear."
Fire crews have arrived from interstate as well as New Zealand and Canada, while a team from the United States will arrive on Saturday.
Total fire bans will be in place on Saturday for the far north coast, New England, the northern slopes, the greater Hunter, greater Sydney, the central ranges and the nortwestern regions.
A Bureau of Meteorology spokesman says winds will ease slightly over the weekend before picking up on Monday.
Fire conditions would be worse in elevated parts of the state, the spokesman told the ABC.
"We will see a return of higher temperatures and quite dry conditions on Monday into Tuesday," he said.
"The winds will pick up, and conditions will still be elevated for fire dangers into next week."
Australian Associated Press