Campaigners have warned that agencies risk having demonstrations outside their offices if they carry out PR work for the Chinese government.
The warning was issued by the Free Tibet Campaign after reports that the Chinese government was in talks with several international agencies.
Matt Whitticase, a spokesman for the group, said any PR agency assisting the Chinese government would be potentially exposing itself to protests.
Pressure groups have met to discuss their strategy to stop the Olympic torch going through Tibet and potential campaigns against PR agencies.
Tactics considered include writing to clients and asking them to reconsider their involvement with agencies.
Major PR firms have been coy about working with the Chinese government.
Ogilvy, Burson-Marsteller and Ketchum have all refused to rule out working for the regime, with the latter saying they would need to consider the brief carefully before making a decision.
Only Hill & Knowlton, which works for the Beijing Organising Committee for the Games, said would not pitch for the business- but only because it wanted to focus on its core brief.