London firm Rosenblatt is trying to persuade the City to invest in a £600 million development project at the port of Huizhou in China, 50 miles north of Hong Kong.
In an unusual move, Rosenblatt is playing the role of merchant bank adviser to the municipal government of Huizhou which is part of Guangdong province, close to the Crown Colony.
Partner Neil Sampson believes the firm's appointment is the first where a Chinese municipal government has appointed a UK law firm to act as general advisers.
He said: "I have been involved with the Chinese over many years and have built up a level of trust which has made this appointment possible. Personal relationships are of the utmost importance in China."
Sampson said he is talking to UK banks, investment groups and civil engineering companies that may want to play a role in building up the port, which will be connected to the nearby city of Huizhou by a new rail link.
Senior partner Ian Rosenblatt said the firm is keen to promote substantial UK and European involvement with the project.
He said: "There are many opportunities for British financial institutions and industry relating to construction, supply of technology and port management."