Lake Macquarie police are examing four fires that began in quick succession at Morisset from 4.30pm on Tuesday.

State Emergency Operations controller Gary Worboys said on Wednesday the vast majority of people had "banded together and supported each other during a time of catastrophic danger".

"It's unacceptable that the actions of these few individuals endangered the lives and property of others, either intentionally or through ignorance," he said.

The cause of fires at North Rothbury and Greta is yet to be confirmed, but the odds of them being deliberately lit firmed on Wednesday when the Rural Fire Service said they were "suspicious".

Police investigators combed bushland off Wine Country Drive the morning after the fire, hunting clues as to how it started only a stone's throw away from homes.

"They were investigated through the course of the day," Lower Hunter Fire Control Centre coordinator Burt Pipan said..

"Those findings will be kept for the Coroner's court.

"There was no lightning around [on Tuesday] but it doesn't mean there wasn't power lines clashing or something like that."

Speculation about a possible fire bug caused angst among residents who had their properties threatened.

"They deserve the full brunt of the law, and then some," North Rothbury resident Kylie Shannon said. "It's disgusting behaviour."

Ms Shannon, her husband Steve and their three children had to flee their home so quickly on Tuesday they had no choice but to leave without one of their pet dogs.

"With how quick that wind picked up and how quick that fire blew over, starting spot fires in our front yard, it's horrible to think that someone could have deliberately done that for a few kicks," she said.

Mr Shannon said: "It could have taken out a lot of homes and devastated a lot of people."

"They just don't think," he said of fire bugs. "They've got no regard for human life."

Their thoughts were echoed by neighbour Aleisha Hodkinson, who had to bolt with her 15-month-old daughter Carly on Tuesday.

"I can't even fathom why someone would do that," she said. "What's wrong with them? It's horrible.

"Someone thinks it's fun to go out and light a fire and put all of our lives at risk."

Ms Hodkinson and her partner Mathew only moved into their "dream home", which backs onto Wine Country Drive, two weeks ago.

The 29-year-old said firefighters had undoubtedly saved her family's home.

"I cannot thank them enough," she said. "We wouldn't be here if it wasn't for them. They're all heroes."

On the western side of Wine Country Drive, where the fire began, a huge collection of historic trains almost came under threat.

Hunter Valley Railway Trust's Chris Richards said it was lucky a catastrophe was avoided by the fire not spreading into the property, which contains thousands of tonnes of coal waste from the old Ayrfield Colliery.

Mr Richards expressed concerns about the waste on the property, owned by the Huntlee developers, in late 2017, calling for action to address its bushfire risk.

He said residents had "no idea they're living next to a tinderbox ready to explode".

Unaware of the danger the coal waste posed, North Rothbury's Steve Shannon said the site's thick scrub was risky enough. He could not recall a hazard reduction burn being conducted.

"Now's the perfect opportunity, if they want to do something, now this is all burned out - clear 30 or 40 metres," he said.

"This is a fairly built up area and it's only getting bigger with Huntlee. If we had a bush fire take hold and the houses started to go up, mate - we'd be in trouble."

Noel McLeod has lived in nearby Rothbury Street for more than 20 years.

The vacant houses damaged by Tuesday's fire border his side fence and garlic plant patch, which "died off" as embers rained down on his yard.

He said he believed the last time firefighters did hazard reduction burning in the bush along Wine Country Drive that caught alight on Tuesday was in 1968.

"It's a bloody disgrace," he said. "It would have made a big difference. The local firefighters need to override them [the Greens].

"The amount of rubbish on the ground - you probably couldn't walk through there it's that thick. It's madness."

His friend Kevin Gunn, who came over on Tuesday to help Mr McLeod extinguish spot fires, agreed.

"If we don't burn the bush, it will burn us," he said.

"You can't beat these sort of fires unless you can run them to somewhere."

Mr McLeod said he was "old enough" to know concerns about the fires being deliberately lit were well founded.