Switzerland could see a deal within the next three to six months to end a long-simmering dispute over how it will hand over data to the United States on wealthy Americans suspected of dodging taxes, Julius Baer Chief Executive Boris Collardi said on Saturday.

We are coming to an important phase in the negotiations. We should have, I hope, a deal in the next three to six months, Collardi told Swiss newspaper Le Temps in an interview.

We are not at war, but there are fundamental differences in opinion, interpretation and approach to regularize the past. It's a process that takes time.

U.S. authorities, which suspect thousands of Americans have used Swiss accounts to evade billions of dollars in taxes, have been conducting a widening criminal investigation into scores of Swiss banks, including Credit Suisse.

The Swiss government has been in talks with U.S. authorities for months to seek a deal to get investigations dropped in return for payment of fines and the transfer of names of clients suspected of tax evasion.

Earlier this month a Swiss parliamentary commission approved a government proposal to allow the country hand over data on clients on the basis of patterns of suspicious behavior.

The Swiss government had hoped that both houses of parliament would address the issue before year-end.

But Swiss newspaper NZZ am Samstag reported that the lower house of parliament was in no rush to approve a deal and would only deliberate the proposal in its Spring session in March, against the wishes of the cabinet who want to draw a line under the deal.

I expect the banks to public ally stand up and say why this business is so important and urgent, Christian Democrat party president Christophe Darbellay was quoted as saying in the paper on Saturday. I'm no longer prepared to take the rap for the banks.

(Reporting by Caroline Copley)