'The successful Beijing Olympics have set the best example for the Shanghai Expo. We should learn from Beijing's successful experience,' the state-backed Liberation Daily newspaper said in an editorial.

Analysts said it might be far more challenging to operate the expo for six months than the Olympics, which lasted for only two weeks.

'This will test Shanghai's capability to receive and mobilise a large number of people, the hospitality of local residents and the public transport system,' said Lu Xiaowen , a professor at the Shanghai Academy of Social Sciences.

He added that making the expo environmentally friendly and guaranteeing food safety throughout the event would also present challenges.

So far, a record 221 countries and organisations have confirmed their participation in the expo, with South Korea and Denmark the latest countries to sign formal agreements.

There are even countries participating that have formal diplomatic ties with Taiwan rather than the mainland.

Even Taipei, Taiwan's capital, will join the expo, in a deal confirmed after the city's mayor, Hau Lung-bin, visited Shanghai in June. Taiwan has not signed up, though, making Taipei its de facto representative.

The large number of participants was an acknowledgement of China's rising power, helped by financial largesse to developing countries, especially African nations, Mr Lu said.

Shanghai plans to invest nearly 29 billion yuan (HK$33.15 billion) on the expo, including 18 billion yuan on construction and 10.6 billion yuan on operating costs. But organisers say the prestige brought by the event is more important than the economics.

'The expo will have more significant influence on cultural integration and technology display for China ... than on driving gross domestic product growth,' said Hong Hao , head of the Shanghai World Expo Co-ordination Bureau, although the city hoped expenditure and revenue would roughly balance.

Work has started on building several structures on the 5.28 sq km expo site along both banks of the Huangpu River, including the landmark China Pavilion. The city will retain several venues after the expo, but plans for redevelopment of the site have not been announced.

Shanghai will have 11 metro lines covering 400km built in time for the expo, including one to the site. The city has just finished a new tunnel under the river connecting expo zones.

The local government has used the expo to improve infrastructure.

A transport hub near Hongqiao airport integrating air, rail and bus transport is now under construction. The hub will also include a station for the new high-speed railway line between Shanghai and Beijing.

A controversial extension of the high-speed maglev train line, which now runs from Pudong airport to the east side of the city, is still under consultation, the Shanghai government said, raising the possibility that it will not be ready in time for the expo.

Zhejiang province recently announced plans to begin building a maglev line between Hangzhou , its capital, and Shanghai by 2010.

Group tickets for the expo will go on sale from September 28. They will cost 160 yuan each, with discounts for the elderly, children and physically disabled. Organisers will also sell evening tickets at lower prices to try to reduce the number of day visitors.

Building boom

Shanghai is planning to spend nearly 29 billion yuan on the 2010 World Expo, of which 18 billion yuan will be on construction

The amount, in yuan, Shanghai is going to invest in the cultural centre: 1.1b