The Swiss Banking Commission has announced a new law that will impose some restrictions on anonymous bank accounts, but its practical effects were expected to be limited.

The law, which was published Friday and takes effect in July, closes a loophole that allowed lawyers and fiduciary trustees in certain cases to deposit funds on behalf of their clients without disclosing their identity.However, the law will not affect the holders of numbered Swiss accounts. The identity of such depositors is already known to a small circle of officials within a bank, who are obliged to reveal the names of the client in the event of criminal procedings.

The law will have no impact on the ongoing legal struggle by the Philippines government to recover more than $340 million allegedly stashed away by the late President Ferdinand Marcos and his associates.

It is also unlikely to shed any more light on unconfirmed rumors that Iraqi President Saddam Hussein has fortunes stashed in Switzerland. The main Swiss banks have denied they hold any of Saddam's funds and the Swiss government says it has no grounds to launch any investigation.

Experts say the main value of the change will be as a potential weapon against tax fraud. The extent to which it will help was unclear, however.

The so-called Form B that provided for anonymity will be abolished on July 1. Banks will have until Sept. 30, 1992, to ask current Form B depositors to identify their clients. In the case of a refusal, the banks are required to stop the business relationship.

Switzerland's powerful banks long resisted the abolition of Form B, arguing that it was unnecessary and that clients seeking discretion would merely turn to Luxembourg and to Liechtenstein, Switzerland's tiny neighbor, as alternatives.

The banks dropped their opposition after talks with regulatory authorities earlier this year, although professional groups representing lawyers and trustees fought the plans to the end.

The regulatory banking commission had argued that the Form B provisions interfered with the ability of banks to meet the provisions of the country's recent money-laundering law.