As bushfires tear through a million hectares of Australia’s east coast, authorities have warned the worst may be still to come.

In one of the nation’s worst-ever bushfire threats, more than 140 fires were burning across the state of New South Wales (NSW) and south east Queensland on Tuesday with the country’s environment department warning they were filling the skies with smoke pollution of “hazardous” proportions in some areas.

In Queensland there were over 60 active fires, and conditions are expected to worsen on Wednesday with strong winds and temperatures in the mid-30s.

It comes after three people died in out-of-control bushfires at the weekend, two of them apparently trying to flee fastmoving fires in cars.

At least 170 houses were estimated to have been razed in fires but no further lives were lost on Tuesday.

New South Wales has declared a state of emergency as parts of the state face a “catastrophic” fire danger, which is the highest level of warning.

Shane Fitzsimmons, the commissioner of the NSW rural fire services said yesterday that a wind change was turning fire fronts sideways and creating a “dead man zone”. He said the forecast for severe weather on Friday meant “we simply aren’t going to get the upper hand on all of these fires”.

Existing fires are continuing to grow rapidly while new ones emerge, with authorities fearing some could continue to rage for months.

“It’s going to be a long, difficult fire season,” he said. “And we have the worst of our conditions typically ahead of us as we come into the months of summer.”

Authorities are now warning the state’s residents not to underestimate the damaging effects of smoke as air quality worsens.

Dust has also contributed to poor air quality in Sydney, Newcastle and the central coast ahead of a southern change that was expected to hit on Tuesday evening, the Bureau of Meteorology said.

Kenneth Turnbull, a vice president of the Turnbull Clan Association who lives in the south east Queensland rural setting of Tamborine Mountain, high up in the hinterland behind the Gold Coast, said he had never been so worried about the bushfire threat. Mr Turnbull, whose father was born in Glasgow, said: “This week has seen a state of emergency declared for Queensland in over 42 communities. Ours is one of these and of concern.

“Over the last week we have witnessed the worst fires we have seen near the borders of NSW and us and it’s still Spring! We can expect hot weather in summer, but this is unprecedented.

“Smoke haze has been the heaviest we have ever known. Yesterday morning we awoke to a very thick smoke haze around our area. From the fires across the border in NSW.

“Like many of us on the Mountain, we have been preparing our things to evacuate if necessary, but so far I think we are safe. I have never been so concerned about the situation we have at present and I have been near fires before.

“The fire chiefs are also saying that they have never seen anything like it. Farmers and many others make the same comments.

“Large swathes of blackened scrub confront many areas.”

He said that yesterday morning they awoke to near clear skies but were informed this would be short lived.

“Gusty winds are expected on Tuesday night and Wednesday which will fan these spot fires and the existing uncontrolled fires again. We are hoping that they don’t head this way on the Mountain. 

“Apart from the immediate physical threat…when authorities issue a message of catastrophic fire danger, the message there is basically, ‘Get out, get away'." 

Clare Nullis, spokeswoman for the World Meteorological Organization said. Experts had compared yesterday’s forecast to the 2009 Black Saturday bushfires in Victoria, when 173 people died.