Coinciding with a state visit to Britain by Chinese President Hu Jintao, London-based consulting firm Arup will announce that it has clinched a deal to work on the self-sustaining urban centres equivalent to the size of a large western capital, The Observer weekly newspaper said.

Arup has already signed up for one such project near Shanghai, said the paper, which added that the eco-cities are regarded as a prototype for urban living in over-populated and polluted environments as well as a magnet for investment funds in China, whose economy is booming.

The signing ceremony was expected to take place at the official residence of British Prime Minister Tony Blair, with the partly state-owned Shanghai Industrial Investment Company acting on behalf of Beijing.

"We are going to help establish a model of how a sustainable city works, but it must also be a viable financial proposition in the long term to attract international investment," the paper quoted Peter Head, the Arup director in charge of the first eco-city Dongtan, as saying.

Head added: "It is no gimmick. It is being led at the highest levels of the Chinese government."

The Dongtan development aims to build a city three-quarters the size of Manhattan by 2040, with the first phase accommodating some 50,000 people, the paper said. Up to four more eco-cities will be built, though exact locations have yet to be revealed, it added.