NSW Health have released a health warning as a large dust storm moving across NSW is expected to engulf Sydney and the east coast.

Air quality in the Sydney Basin is expected to worsen during the day before a cold front brings rain later on Wednesday afternoon.

Dust storms can cause havoc for the population. Credit:Peter Rae

In northern parts of the state levels of dust are forecast to increase in the afternoon and evening.

Director of Environmental Health, Dr Richard Broome said people with chronic respiratory and cardiovascular conditions should cut back or reschedule strenuous outdoor activities.