A dust storm could form over the next few days that could impact Canberra and Sydney, and it could rival a dust storm that hit Sydney in 2009, the Bureau of Meteorology says.

Key points: Drought conditions have resulted in dry soils, which makes it easier for wind to pick up dust

Drought conditions have resulted in dry soils, which makes it easier for wind to pick up dust A cold front generating strong winds is moving towards NSW

A cold front generating strong winds is moving towards NSW The whole NSW coast is potentially at risk, but it will depend on how strong the winds are

Bureau weather services manager Jane Golding said the chances of a dust storm forming this week were "pretty high".

At the moment conditions are looking similar to those that led to the Sydney dust storm of September 2009, which blanketed Sydney as well as swathes of NSW.

It also caused flights to be re-routed to Brisbane and Melbourne, smoke alarms to go off, and there were more than 130 calls for help due to breathing difficulties.

Could it be another 2009?

Drought conditions have led to dry soils and limited vegetation, which makes it easier for the wind to pick up dust.

There have already been a number of dust storms in western NSW this year, where the visibility got down to less than 500 metres.

But what could set this one apart is the strength of the winds.

Ms Golding said if the atmosphere evolved in the way computer models were suggesting, it could be similar to the 2009 event.

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What is triggering the situation?

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A cold front that moved through South Australia yesterday, with a low pressure trough over New South Wales, is responsible for current conditions.

The north-westerly winds dragged moisture down into NSW, which has resulted in potentially severe storms forecast for eastern parts of the state.

"What happens in the next couple of days is that front starts to move into New South Wales," Ms Golding said.

"On Wednesday it kind of pokes into the western part of the state and then on Thursday it moves across to the east.

"The other thing the computer models are forecasting to happen is for a deep low pressure system to develop near South Australia [on Wednesday] and track to the south of New South Wales on Thursday.

"A frontal system generates some really strong westerly winds, and that frontal system ends up producing a low pressure system to the south of the country which picks up even more vigorous winds."

Sorry, this video has expired Dust storm hits Broken Hill

But these big events are rare for a reason — they need all the factors to align.

Ms Golding said it was early days, and it would only take a couple of little things to back off and it would be a different story.

"The wind strength would only need to be a little bit less for that not to happen. But it's certainly something we're watching."

Where could the dust get to?

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There are several source areas the dust could be gathered from before spreading across NSW:

The inland plains near the South Australian border

The inland plains near the South Australian border Lake Eyre basin and South Australian inland lakes region

Lake Eyre basin and South Australian inland lakes region South-west Queensland Channel Country

Ms Golding said the whole NSW coast was potentially at risk, including Sydney, but it depended on how strong the winds were.

"If the winds are gale force it might make it all the way to the coast," she said.

"If they are down in the fresh range, so maybe only around 40 kilometres an hour … the dust might not even make it to Canberra.

"At the moment the guidance is pointing to some pretty strong winds, but we'll just have to see how the front and the low pressure system develop."

A surfer at Bondi Beach during the September 2009 storm. ( AAP: Tracey Nearmy )

How to prepare

A Queensland Health spokesperson said in the event of a dust storm, people with respiratory issues should stay indoors with windows and doors closed, and avoid vigorous exercise.

"If you are experiencing any adverse reactions to the dust, such as shortness of breath, prolonged coughing or wheezing, seek medical advice."

More information on how to avoid or reduce the impact of dust storms can be found on the NSW Health website.