Operating under the title of 'The UK Engineering Design Academy Limited', the group has set up a website,
www.ukpla.co.uk, registered in Hong Kong in August 2006.
It is believed that this could be used as a way of winning work in mainland China, where some potential clients may not be aware of the authorship of the UK's building stock.
Both Hopkins and Fosters are investigating the options open to them, after being made aware of the site.
On the website, the phoney firm claims to have '18 branch offices throughout the UK'.
'Furthermore', the website states, 'the company has established many foreign offices in Europe, East China, Asia and America. Moreover, our designers have rich experience in many design fields.
'By January of 2006, the total number of designers in the company reached 3,800,' the website claims.
However, the company's registered address is a PO Box number in north-west London, and Companies House has no record of the firm's existence before August 2006.
The British telephone number listed on the website diverts to a number with a foreign ring-tone and is answered by a Chinese person unable to speak English.
Other British buildings which those behind the website claim to have helped design include Vauxhall Tower, by Broadway Malyan, and Evelina Children's Hospital, also designed by Hopkins Architects.
Henry Buxton, a Hopkins director, told the AJ: 'The bottom line is that it looks like these guys are using our projects to look like they are a major firm of designers to get work in China.
'They have clearly stolen all the images they have on the website. It is ridiculous.
'We are taking steps [between us] to try and take the website down. We can't see how to stop this happening.
These things are likely to happen more and more, especially in this internet age'.
Another practice on the receiving end of the sting was Northamptonshire-based GSS Architects, whose work at the Sponne School in Towcester, features on the website.
'I suppose we should be flattered that they were so impressed with our work that they should claim it as their own,' said director David Allsop.
'We've spoken to our legal advisers, but I suspect there is very little we can do. Perhaps we should claim to have designed the Great Wall of China.'