A truck catches fire. Credit:Nick Moir Two firefighters had to be treated for burns and five others required treatment for serious smoke inhalation. Another was taken to hospital with chest pains. Sydney was covered with a smoky haze on Tuesday afternoon, after the city's hottest temperatures for early spring - it remained above 20 degrees through the night, and reached record-breaking tops in excess of 31 degrees, higher in the city's west. Combined with dry winds gusting to 80km/h, and bushland in western Sydney that had less than 10 millimetres of rain last month, conditions were ripe for fire. NSW Rural Fire Service said the cause of the major fire near Sydney would be investigated. While fires were brought under control near Cooma and on the south coast, the ACT region was spared the extreme conditions found in Sydney and further north - winds were slightly lighter, humidity was higher, temperatures were significantly cooler, and the overall fire danger was rated as low. ACT Rural Fire Service chief Andrew Stark said the situation in Sydney was a sombre reminder for the rest of NSW and the ACT that fire season was quickly approaching.

''It's not unusual to get this type of activity at this time of year,'' he said. ''August-September traditionally have quite windy days in south-east Australia, and if you happen to get some warm weather with those windy days, then you can have bushfires break out. ''We always urge people to be prepared, to start their preparations early, and, if anything, a day like [Tuesday] with this type of activity in Sydney is a good reminder to the residents of the ACT region that another summer is coming and the potential for bushfires will come with it, and people really need to think about preparing their plan and preparing their properties for bushfires.'' The bushfire season in the ACT and the associated restrictions on lighting fires officially begins on October 1, but Mr Stark said the RFS would begin receiving two specialised forecasts regarding fire conditions every day from next week. Mr Stark said large hazard reduction burns in Namadgi in autumn and a good number of dry days over winter meant the ACT RFS was on top of its hazard reduction program. The Bureau of Meteorology was predicting a higher possibility of rain from late October through November.

Just last week, a warning was issued from the Bushfire Co-operative Research Centre for above-average fire potential in the ACT's grasslands, as predicted rainfall could fuel vegetation growth. ''I have to prepare for a bad season, regardless of what the forecast is,'' he said. ''Conditions can change very quickly, just like we saw last summer.'' The severe weather conditions in Sydney were due to ease slightly late on Tuesday as a low pressure trough made its way across the south-east. Meteorologist Rob Sharpe from Fairfax-owned Weatherzone said the hot air mass over central Australia, responsible for much of Canberra's warmth and for the heat in Sydney, would shift further north over the coming week, allowing for some colder air to move in from the south. Loading

''What we're going to see over the next little while is that heat is going to stay over northern Australia because we're going to have a couple of low pressure systems and associated troughs moving across southern Australia and into the east. That's going to bring some rain into Canberra, but the focus of that is going to be southern parts of South Australia, Victoria, and Tasmania,'' he said. Mr Sharpe said temperatures would drop closer to average over the next week, with the chance of a few showers.