UBS has dismissed claims made in a recently published book that it had systematically helped wealthy French clients to evade tax, saying the claims were based on comments from disgruntled former staff.

The claims made in the book entitled Ces 600 milliards qui manquent a la France - or The 600 billion missing from France - were "false and ungrounded”, reports quoted the Swiss bank as saying.

"UBS strongly rejects these false allegations and will defend itself against them vigorously using the appropriate legal means," UBS told WealthBriefing.

The book's author, French journalist Antoine Peillon, claims the Zurich-based bank schooled its client advisors in how to target businesspeople and celebrities, and avoid being caught by French authorities.

"The allegations stem from several former
employees in France, who have made claims against UBS (France) SA based
on their previous employment and who have brought various charges
against UBS (France) SA. The court has neither responded to these
claims nor confirmed them. UBS (France) SA has conducted an internal
investigation, in which it found no evidence that would support the
allegations," the UBS statement said.