Paisner & Co is in talks with its French ally, Uettwiller Grelon Gout Canat & Associes (UGGC) and a Dutch firm, in a bid to set up a pan-European alliance.
The 44-partner City firm also wants to persuade a German, an Italian, and a Spanish firm to join the venture.
But the firm is initially concentrating its efforts on strengthening its existing five-year alliance with 50-lawyer UGGC – and is understood to be in the process of persuading a medium-sized Dutch firm to join the alliance.
It is hoping to begin partner exchanges with UGGC in a bid to form closer links between the two firms, which already conduct joint marketing exercises.
The two firms eventually hope to merge.
Senior partner Harold Paisner said: "We need a European firm, with an ultimate goal of more than an alliance.
"Smaller firms cannot commit the finance to start stand-alone offices."
UGGC managing partner Jean-Francois Canat said: "Our goal is to be closer and one day we may merge."
Paisner & Co recently appointed its first managing partner, Stephen Rosenfield as part of a restructuring exercise to prepare the firm for expansion.
It currently has no European offices, although UGGC does have a Brussels office. An alliance with US firm McDermott Will & Emery broke down two years ago, following its decision to start a UK practice.
Paisner & Co is the latest UK firm to set its sites on a European alliance, following in the footsteps of Linklaters & Alliance, Cameron McKenna's European venture, (CMS) and Paris firm Moquet Borde, which is poised to announce its own alliance (see story, page 6).
Earlier this month Legal Week revealed that Pinsent Curtis was in talks with German firm Shurmann & Partners.
Eversheds and Dibb Lupton Alsop have both announced plans to establish a European alliance. Eversheds recently rebranded itself as a European law firm, while Dibbs claims to be in talks with firms in four European countries.