Large areas near Broken Hill, White Cliffs and Menindee were swallowed up by the huge dust cloud on Wednesday afternoon.

Bureau of Meteorology predictions show the dust will continue to move in an easterly direction possibly towards the Hunter on Thursday.

“Dust storms may reach as far as the coast on Thursday, including Sydney and Canberra, and strong winds will also lead to elevated fire dangers for eastern NSW,” meteorologist Jonathan How said.

Meanwhile, NSW Health has issued a warning to those with a respiratory or cardiovascular condition to limit the amount of time spent outdoors and avoid vigorous exercise.

The warning also stated that dust particles vary in size from coarse (non-inhalable), to fine (inhalable), to very fine (respirable).

“Coarse dust particles generally only reach as far as the inside of the nose, mouth or throat,” the warning stated.

“Smaller or fine particles, however, can get much deeper into the sensitive regions of the respiratory tract and lungs.

“These smaller dust particles have a greater potential to cause serious harm to your health.”

The NSW Health statement said commonly, particles in dust storms tend to be coarse or non-respirable and do not pose a serious health threat to the general public.

“However, some people with pre-existing breathing-related problems, such as asthma and emphysema, may experience difficulties,” it said.