(Adds details of Credit Suisse investigation, potential plea)
ZURICH/WASHINGTON, May 2 (Reuters) - Switzerland's finance minister was set to meet Eric Holder, the U.S. attorney general, in Washington on Friday to discuss a tax-evasion probe into Swiss banks by U.S. authorities, a Swiss ministry spokesman said.
Contacted by phone, the spokesman said the minister, Eveline Widmer-Schlumpf, would push for "fair and equal treatment" of the Swiss banks involved in the probe.
U.S. prosecutors have been pushing for Credit Suisse , the biggest Swiss bank in the probe, to plead guilty as part of a resolution of the investigation, a person familiar with the matter said.
U.S. Department of Justice officials met with U.S. regulators last month to make sure that such a plea would not cripple the bank's ability to do business in the United States, the source said.
Credit Suisse came under more pressure this week as a former employee pleaded guilty to helping U.S. clients avoid taxes.
"The United States Department of Justice's investigation into the U.S. tax matter remains outstanding and, while we are working hard to bring this to a close, the timing and outcome remain uncertain," Credit Suisse said in its quarterly report on Friday.
The bank declined to comment further on the latest talks.
More than a dozen Swiss banks, including Julius Baer and the Swiss arm of Britain's HSBC Holdings Plc , are under criminal investigation in the United States to determine if they helped wealthy Americans hide money from the tax man.
Scores of smaller banks have agreed to work with U.S. authorities in order to cap penalties they might face.
(Reporting by Oliver Hirt and Silke Koltrowitz in Zurich and Aruna Viswanatha and Julia Edwards in Washington; Editing by Jeffrey Benkoe)