The Swiss government, in an unusual move, today halted all financial transactions on bank accounts belonging to Philippine ex-president Ferdinand Marcos and his family after unknown persons reportedly tried to withdraw some of the money yesterday.

A government spokesman in Bern, the Swiss capital, said orders had been given to six Swiss banks, which he did not name, to freeze "any assets in Switzerland held by the Marcos family and persons, companies and the like connected with them." A government announcement said the freeze followed evidence made available to the Swiss government yesterday that Marcos was trying to pull funds out of Switzerland.

The Swiss government is scheduled to take up the matter Wednesday. Informed sources said a special emissary representing the Philippine government of President Corazon Aquino was en route to Switzerland to discuss ways for Manila to recover the money.

A spokesman for the Swiss Bankers Association, which is responsible for supervising Swiss banks, said the association was "somewhat astonished" that the government had ordered the freeze. There were indications that bankers were taken by surprise, not only by the nature of the move, but the speed with which the government was making decisions.

The secrecy laws governing the banking system here are considered almost sacrosanct. International banking is an important segment of the Swiss economy.

Documents brought to the United States by Marcos and made public last week indicate that he controls tens of millions of dollars of deposits in Swiss Bank Corp. and Credit Suisse. Marcos' accounts in these two banks comprised more than half the bank account deposits listed in the documents.

Other records obtained by The Washington Post indicate extensive Swiss banking by Marcos' close associates as well. Glyceria R. Tantoco, wife of the former Philippine ambassador to the Vatican and alleged by U.S. and Philippine investigators to be a "front" for Imelda Marcos, transferred $3.2 million between last August and January 1986 to an account at Credit Suisse from a New York bank account, the records show.

Two weeks ago, members of a Philippine commission investigating Marcos' "ill-gotten wealth" said they have information about an $800 million Swiss bank account held by Marcos. They have not provided additional information.

Swiss secrecy laws forbid the banks to divulge who has what money in what accounts, or even whether certain persons have an account with the bank. But the bankers' association, in an unusual statement last Friday, said that "banking secrecy is not absolute and does not protect criminals."

Swiss banks are obliged to furnish information to a court when criminal proceedings under Swiss law are involved, the bankers' statement said. A spokesman for Swiss Bank Corp., one of the largest banks, said he understood the Philippine emissary would seek to open such proceedings here, which would enable the funds to be recovered if the court found a criminal act had been committed.

A creditor, in this case the Philippine government, could have the assets seized by a court decree and would then have to press claims within a fixed period.

It was not clear who had tried to withdraw money from Marcos' accounts in Switzerland. Swiss Bank Corp. spokesman Yves Sohrmann said the order affected what he termed "all potential Marcos money" in his bank's branches throughout Switzerland, but not in other countries.

Rainer Gut, chairman of the board of Credit Suisse, told the bank's annual meeting last week that the bank had some "modest" professional involvement with the Philippines, with an investment of about $20.83 million. But he declined to answer questions about any personal accounts in the name of Marcos or his family.

Staff writer Dale Russakoff added in Washington:

Congressional investigators probing Marcos' hidden wealth met for almost five hours with the deposed leader's alleged New York real estate agents, Joseph and Ralph Bernstein, who face contempt of Congress charges for refusing to cooperate earlier.

A spokesman for Rep. Stephen J. Solarz (D-N.Y.) said the Bernstein brothers appeared willing to cooperate with the probe of his Foreign Affairs subcommittee. The meeting came hours after Solarz had testified before a federal grand jury considering the contempt charge.

The Bernsteins manage three of five New York properties alleged by Philippine and U.S. investigators to belong to the Marcoses. Their testimony appears crucial to the new Philippine government's court fight to seize the properties, valued at $350 million.

Investigators last week made public a 1982 trust agreement showing that Marcos had empowered Joseph Bernstein to act on his behalf in running one of the buildings, known as the Crown Building. Another document showed that money from a Marcos bank account helped buy another, the Herald Center, also managed by the Bernsteins.