Swiss and US negotiators need more time to finalize a settlement in a high-stakes attempt by the US government to obtain names of suspected American tax evaders from Swiss banking giant UBS AG, a Justice Department attorney told a federal judge yesterday.

US District Judge Alan S. Gold set another status hearing for Wednesday and pushed off a trial until Aug. 17.

The trial has already been delayed three previous times, and Gold has said it will take place only if a final agreement is not reached.

The Swiss and US governments last week announced an agreement in principle on major issues, with plans to present a final deal at yesterday’s hearing.

But resolving the details has proven more difficult than both sides envisioned.

“There are still some issues that remain to be resolved,” Stuart Gibson, the lead Justice Department lawyer in the case, told the judge on a conference call.

Eveline Widmer-Schlumpf, head of the Swiss Justice Ministry, said in a statement that negotiators “will continue to work intensively to clarify the details of the settlement.”