Mills & Reeve, the East Anglian-based firm, is seeking to expand the operations of its Birmingham office by competing for private sector work with the city's leading firms.
The office currently deals with medical negligence work for NHS trusts and insurance litigation.
But the firm is planning expansion, almost certainly through a merger, The Lawyer can reveal.
Managing partner Duncan Ogilvy says: "It is easy to imagine us expanding our practice from the NHS to other public sector and quasi-public sector markets such as local government and universities on our own.
"But a step into the private sector in Birmingham would be unlikely to happen without an amalgamation."
When the office opened, Ogilvy said it would not compete with fellow former Norton Rose M5 Group member Wragge & Co because it would cover only insurance work.
Ogilvy says this remains the firm's current position but it is thinking about other options.
The practice opened with partner Stephen King and two assistants, but after last September's merger with Birmingham firm The Lewington Partnership it has grown to 180 lawyers, says Ogilvy.
He adds that, despite the success of the Birmingham office, the firm's Cambridge commercial base remains the heart of the business.