ZURICH (Reuters) -UBS finance chief Todd Tuckner voiced his disappointment on Wednesday over proposed new Swiss capital regulations, which he said was the beginning of a possibly long process that the bank intends to contribute to.

"Naturally, as to capital, we're disappointed," Tuckner said at a conference in Berlin, speaking days after the Swiss government proposed rules that could make the country's remaining big bank hold $26 billion more in core capital.

"We are looking at every possible option to potentially mitigate the imposition of these extreme capital measures," he added.

UBS planned to engage in political consultation processes on Switzerland's capital requirements, which could eventually lead to a more proportionate outcome, Tuckner said.

Expecting a phase-in period of four years or more for stricter capital deductions rules on deferred tax assets and software was reasonable, Tuckner said, while reconfirming the bank's 2025 capital return expectations and 2026 targets.

"In terms of longer-term ambitions that we've talked about in the past, we have to see what the timeline ultimately is and have more visibility around the rules."