Martineaus' move coincides with the arrival of Chris Moseley from mobile phone operator Orange, who will lead the telecoms team. Moseley spent three years as a legal assistant at Orange.
Moseley says Martineaus has set up the telecoms group to gain business from the creation of a fifth mobile phone company in March and the "third generation" licensing process.
He says: "The Government has stipulated that a condition of being able to bid for any of these third generation licences is that any existing operator must undertake to provide access to new entrants."
The group will draw on lawyers from the firm's trade and utilities department, headed by partner Geraldine Tickle, as well as the corporate, finance and property practices.
Tickle says: "There has been a huge expansion in the mobile phone market in the past few years and there is considerably more to come.
"Technological advances are driving the rate of change in the telecoms sector at an amazing speed, and there is a genuine need for more legal expertise in this field to keep pace with what is happening in the marketplace."
Moseley says: "We intend to offer the service irrespective of where the client is, on the basis that we are centrally located."