SYDNEY (AFP) - A hugely destructive cyclone described as a "perfect" storm is bearing down on the isolated northern Australian city of Darwin, devastated by a killer cyclone in 1974. Packing winds of up to 350 kilometres (218 miles) an hour, Tropical Cyclone Monica was moving relentlessly towards Darwin as it turned towards the coast from the Arafura Sea, the government's weather bureau said. "It's probably the best developed cyclone I have seen in many, many years," said David Alexander, a senior forecaster at the Bureau of Meteorology. "It's got a perfect circular eye, it's right at the top of a category five range, so it's a very, very severe cyclone." Category five is the highest and most dangerous ranking for a tropical cyclone. The 1974 storm which killed 71 people and left 20,000 homeless in Darwin, Cyclone Tracy, was a category four storm. Darwin, capital of Australia's sparsely populated Northern Territories, is now a rebuilt city of 100,000 people, with many new buildings designed to withstand severe storms. Alexander said Monica was far more dangerous than Cyclone Larry, which smashed into Australia's eastern Queensland coast less than a month ago, causing more than a billion dollars in damage. The "very destructive core of Severe Tropical Cyclone Monica, with gusts to 350 kilometres per hour" was expected to cross the coast later Monday and approach the Darwin area on Tuesday, the government's weather bureau said. Destructive winds with gusts of up to 160 kilometres an hour were already hitting the far north coast and dangerously high tides could cause extensive flooding, the bureau's Tropical Cyclone Warning Centre reported. Shortly after midday Monday, Monica was 440 kilometres east northeast of Darwin, moving west southwest at 13 kilometres an hour. The storm has already disrupted commercial fishing, with many of the 75 prawn trawlers operating in remote off-shore regions heading for safety in port, national radio reported. Mining operations were also hit, with uranium miner Energy Resources of Australia, majority-owned by mining giant Rio Tinto, shutting down its Ranger mine 250 kilometres east of Darwin. US-based aluminum manufacturer Alcan closed its Gove refinery in north-east Arnhem Land on Sunday but reopened Monday after the storm missed the area. Police had evacuated most of Goulburn Island off the Arnhem Land coast but small clusters of people remained on other islands, mostly populated by Aboriginal people, ABC radio reported. "We've got a couple of areas we can go and hide. If the worst comes to worst we can go and stand in the cool room," said store manager Ian McDowell, one of the few residents who opted to remain on Goulburn Island. Ranger Peter Fitzgerald, one of a tiny group of people staying at Black Point on the Coburg Peninsula in the direct path of the cyclone, said: "I think we'll be okay -- just don't do anything silly that's the main thing." Northern Territories Emergency Services Minister Paul Henderson warned people to prepare cyclone kits including medicines, food and water, a torch and radio, while hospitals in Darwin were making contingency plans to cope with any casualties.