Competition lobbying experts believe the proportion of the two firms' turnover earned in Europe is sufficient to attract the attention of the European Commission.
It is likely that Competition Commissioner Mario Monti would object to the market share the merged firm would boast on certain routes, and look to impose conditions on the approval of the bid.
Several routes including those between London and Barcelona, Nice and Belfast, would see the new airline enjoy a market share in excess of the 40 per cent level at which competition authority interest is triggered.
It is understood the PR handling of the combined firm would also be subject to review should the acquisition go ahead. The Go brand is expected to disappear after the move, and much of the management of the firm would also fold into one company.
Despite its project-based link with City PR firm Grandfield, the easyGroup is known to favour the use of in-house resources for communications, which calls into question the future of Cohn & Wolfe's work with former BA subsidiary Go.
The agency provides a full service to the airline, which has no in-house communications team or press office of its own.
Cohn & Wolfe director Brandon Stockwell said it was 'too early to comment' on what effect the potential takeover would have on the account.
He added that no further agencies had been recruited to work on Go's behalf, insisting: 'It's a 3i deal not a Go deal'.
Venture capitalist 3i is being assisted by recently appointed lobbying agency Bell Pottinger Public Affairs, while easyJet's in-house team and Grandfield are handling its side of the deal.