A Japanese developer has resumed work on the world's tallest building in Shanghai, placing an US$800 million (HK$6.2 billion) bet on the future of the property market in the mainland's commercial centre. The 492-metre Shanghai World Financial Centre will top the Petronas Twin Towers in the Malaysian capital of Kuala Lumpur, currently the tallest building at 452 metres. Work on the building started in 1997, but ground to a halt in the wake of the Asian economic crisis. The massive 30,000-square-metre plot in the premier Pudong development zone lay dormant for five years. At a ceremony yesterday, Japan's Mori Building Co and 33 Japanese financial institutions and companies formally marked resumption of construction on the redesigned 101-storey skyscraper. The group intends to seek additional equity investors. 'The investment environment for Shanghai's property market has improved because of government policies and economic development,' Mori Building president Minoru Mori said. Other buildings with a claim to the world's tallest title are now under planning, including a replacement for the World Trade Centre which was destroyed in the September 11 attacks. The Shanghai World Financial Centre will be finished in mid-2007, in time for the 2008 Beijing Olympics. Architects Kohn Pedersen Fox Associates said the new design was basically unchanged, but the building would now be taller and updated with advances in technology and safety. Designers retained a circular opening at the top of the building, which originally sparked controversy because some said it resembled Japan's wartime 'rising sun' flag - serving as a reminder of that country's military actions on the mainland during World War II. Architects said the feature was necessary to stop the building swaying during high winds. They said the design was intended to resemble a traditional Chinese 'moon gate'. Plans for many skyscrapers have been shelved in the wake of September 11, but Shanghai is keen to have a landmark building as it strives to become a regional financial centre. The new building will put 377,300 square metres of total floor area on to the market. Most of the building - about 60 per cent - will be office space. Property analysts cite strong demand for office space in the area where the building is located - Lujiazui, Shanghai's 'Wall Street'.