Firefighters in the north of New South Wales are battling a blaze which is threatening houses and a World Heritage-listed National Park. The fire has already entered the park area at Mount Warning. The intense fire appears to have started from a hazard reduction burn on private property south-west of Murwillumbah. The Rural Fire Service has six units battling the blaze and back-burning has been undertaken around six homes to protect them. The fire has now entered the World Heritage-listed Mount Warning National Park and there are grave concerns it will cause severe damage to the delicate area because of its inaccessibility.