The top 20 firm is also planning a move from its current Merchants House office in order to handle the increased capacity.
Camerons currently has around 50 lawyers based in the South West, but it is now looking to grow this number to as many as 150 over the next three to five years.
The bigger office is expected to handle much the same work as its City counterpart, with the move being described as a form of “in-house outsourcing”. The firm will not compete for local work in the city.
Senior partner Richard Price said: “We’re not doing this from Mumbai or wherever else, and it’s not about servicing the Bristol market.”
The firm’s head of real estate Edward Benzecry will become the first high-profile partner to head west when he stands down from his role and relocates in May.
Price added: “Edward going down sends a message to our partnership about what we want to do in Bristol. There are certain areas of our work we can do from there.”
Benzecry is expected to be replaced as real estate chief by Mark Heighton after eight years leading the team.
There has been speculation that Camerons would use either Bristol or Aberdeen to effectively outsource London work, but the Aberdeen office is now expected to remain the focus of its UK energy practice.
Price said: “Both Aberdeen and Bristol are important, but Aberdeen will grow organically.”