GENEVA: UBS chairman Kaspar Villiger said in a newspaper interview on Sunday that he could not entirely rule out that some staff at the Swiss bank might have assisted tax fraud in other countries.

"With 70,000 employees I cannot put my hand in the fire and say there will be no more problems," he told the Swiss newspaper NZZ am Sonntag after being asked about the possibility.

"I do believe that this systematic act only occurred in the case of the United States," added Villiger, who joined the bank in April.

Villiger said those responsible had been rooted out, while the risk of further problems for UBS with charges of assisting tax fraud in the United States were "very, very limited" following the deal revealed by Swiss and US governments last Wednesday.

He cautioned that UBS faced a major task in reforming its business culture.

"We need to return to the profit zone swiftly. To do so we are refining our strategy and working on a new corporate culture, which is a herculean task with 70,000 people," said Villiger.

That included being "absolutely certain" that staff worked within the law.

"A show trial that stretched over several years and regularly filled the headlines would have been extremely damaging for the bank," he said.

"For the future it is really very important that we build a culture in which such lone ventures are no longer possible," Villiger added.

Canada's national revenue minister Jean-Pierre Blackburn said Friday that tax officials plan to meet with UBS in the coming weeks in a bid to uncover Canadian fortunes that might be hidden in offshore accounts.

The move comes on the heels of the landmark Swiss-US agreement settling a bruising lawsuit by US authorities against the Swiss bank, allowing account information to be disclosed in their hunt for tax evaders.

US authorities also fined UBS 780 million dollars in February in a similar tax-related case where the Swiss bank accepted full responsibility for "improper activities."