A great white shark lurking off the beaches of Newcastle, 160 kilometres north of Sydney, has forced lifeguards to close the city's beaches for a record seven days, news reports said Friday, according to dpa. But with temperatures hitting 30 degrees many local surfers and spearfishermen ignored the warnings and were seen in the water less than 200 metres from the 5-metre, 1,700-kilogram shark, the Daily Telegraph reported. Marine biologist from Southern Cross University Dr Daniel Bucher told News Ltd it was very rare for a shark to stay around a coastal area for so long, and it might be necessary to take action. "If you've got a shark that is a real and imminent danger and doesn't want to leave an area, there might be a case for targeting that individual shark," he said. "But it's such a rare event. If a shark is hanging around one particular area, yes it is a possibility that once it finds it can eat people it might start to hang around and shift its habits to take on a new reliable food source." Lifeguards have tried to move the shark out of the beach area by buzzing it with boats and surfskis but so far it refuses to move. Other sharks were also reported close to the shore. A photographer in a helicopter witnessed a 3.5-metre tiger shark at a beach nearby attacking a dolphin, taking a huge bite from its back, news.com.au reported.