Much of Australia is in the grip of an extreme heatwave with temperatures expected to reach into the mid-40s and total fire bans in force in parts of South Australia, New South Wales and Victoria. In South Australia, 47C was forecast for Maree, a small town in the north of the state, and 46C in Renmark and Port Augusta. The state capital of Adelaide was expected to hit 38C on Saturday. An extreme bushfire risk has been declared for the Adelaide Hills. On Friday, a grassfire north of Adelaide burnt through 650 hectares. The state’s Country Fire Service is advising those in the at-risk districts to put their bushfire plan into action and keep track of any updates. In the town of Coober Pedy in northern South Australia, where 46C was forecast for Saturday, about two-third of residents live in underground dug-outs. “Whilst people in dug-outs will be fine today, we really are concerned about the people that live above ground in housing, in houses above ground and also people that are visiting from other parts of the state, particularly from up north,” Coober Pedy district council chief executive Dean Miller told the ABC. “We’ll be looking out for people to make sure they stay hydrated and have access to water and shade.” In the state of New South Wales, temperatures were expected to exceed 40C across the west and in coastal areas. 45C had been forecast for in Hay and Deniliquin on Saturday and 40C for western Sydney. The south-west of the state was expected to experience the worst of the fire conditions on Saturday, before the sweltering weather moves through Sydney, the Hunter region and north coast on Sunday. NSW Rural Fire Service deputy commissioner Peter McKechnie urged residents to have a fire plan ready and prepare their properties. “This is the first time since the devastating season last year we’ve seen widespread elevated fire danger,” he said. “Know what to do if a fire threatens you, know where you’ll go.” In Victoria, the north-west town of Mildura was forecast to reach 45C on Saturday – its previous record for November was 45.5 in 2012. Swan Hill was forecast to hit 44C and Echuca was expecting 42. The Country Fire Authority has declared fire bans for the Mallee, Wimmera and Northern Country regions. Gusty winds were also forecast for Saturday, particularly in the north-west, plus thunderstorms in the afternoon and evening. “The Mallee district will reach an extreme fire danger rating for the first time this season due to the forecasted gusty winds and increased grassland curing in the area,” CFA acting chief officer Alen Slijepcevic said. “Northern Country and Wimmera will also experience elevated dangerous fire conditions, with a severe fire danger rating. “As a result, we have declared a total fire ban across all three weather districts.” In south-east Queensland, the heatwave is expected to last into mid-next week. Reinforcements were being sent to the state’s Fraser Island to help contain an out-of-control bushfire that has been burning for the past six weeks. Tourists have been ordered to stay away from the blaze, which has burned through 74,000 hectares so far, and stay off the island’s inland tracks and roads. Hotter, drier winds with the potential to carry the fire in a southerly direction have been forecast over the weekend. The blaze is believed to have been started by an illegal campfire on 14 October. Last summer’s bushfires in Australia destroyed 2,476 homes, claimed 26 lives and burned 5.5 million hectares of land.