More emergency service units have been sent to the fire which the after being called an hour ago.
Read the original story here: Thirty tonnes of straw burns in Hunston fire
The fire is at the rear of Swan Cottage on Selsey Road, Hunston.
A spokesman for West Sussex Fire and Rescue Service said that it is not working with other emergency services at this time.
The spokesman originally said: "We were called to the incident at 11.08am on Selsey Road and there are two fire engines in attendance. 30 tonnes of straw is alight."
West Sussex Fire and Rescue have now confirmed that 'at least' 30 tonnes are alight and members of the public are being told to stay way and those living in the Hunston area are being told to keep doors and windows shut.
There are four fire engines, two land rovers, one water carrier and one command unit.