The warning is for people in South Coast, Southern Tablelands, South West Slopes, Snowy Mountains, Australian Capital Territory and parts of Hunter, Metropolitan, Illawarra, Central Tablelands, Central West Slopes and Plains, Riverina, Lower Western and Upper Western Forecast Districts.

The warning was issued at 2:37 pm today.

Severe thunderstorms are likely to produce large hailstones, heavy rainfall that may lead to flash flooding and damaging winds in the warning area over the next several hours.

Locations which may be affected include Batemans Bay, Orange, Canberra, Goulburn, Wagga Wagga, Albury, Cobar and Bourke.

Damaging wind gusts are more likely west of the Divide, and may locally raise dust. Heavy rainfall and large hail are more likely for eastern parts of the state.

The State Emergency Service advises that people should: 

* Move your car under cover or away from trees. 

* Secure or put away loose items around your house, yard and balcony. 

* Keep at least 8 metres away from fallen power lines or objects that may be energised, such as fences. 

* Report fallen power lines to either Ausgrid on 131 388, or Endeavour Energy on 131 003 or Essential Energy on 132 080, as shown on your power bill. 

* Keep clear of creeks and storm drains. 

* Don't walk, ride your bike or drive through flood water. 

* If you are trapped by flash flooding, seek refuge in the highest available place and ring 000 if you need rescue.

* Unplug computers and appliances. 

* Avoid using the phone during the storm. 

* Stay indoors away from windows, and keep children and pets indoors as well. 

* For emergency help in floods and storms, ring the SES (NSW and ACT) on 132 500.