 Six New Zealand firefighters were injured on Saturday while battling bushfires burning across southeastern Australia, but mild weather reduced the threat of dozens of fires. The cooler conditions helped more than 4,000 firefighters working in rugged mountains and bushland put control lines in place in a bid to slow blazes which have scorched more than 550,000 ha (2,100 square miles) of land. Police say more than 30 homes have so far been razed. The six New Zealanders, part of a group of volunteers who specialise in remote area firefighting, were trapped when a blaze unexpectedly overwhelmed their position near Mansfield, 180 km (110 miles) northeast of Melbourne. They were airlifted to hospital suffering burns and smoke inhalation. One was in critical condition, Victoria Rural Ambulance spokesman John Mullen told journalists. Australia faces extreme fire danger this summer due to a drought. Bushfires are a regular feature of the summer and over the past 40 years, more than 250 people have been killed in bushfires. Scientists fear climate change will bring more frequent higher temperatures and less rainfall.