Money is said to have been transferred from several countries through Israel

On Sunday police arrested 25 staff working at Bank Hapoalim, 15 of whom have since been released.

Staff are thought to have been involved in an operation worth hundreds of millions of dollars.

Police have since arrested one bank customer and said they had "serious suspicions" about 45 other people.

Further probing

The affair is believed to be one of the largest financial scandals in Israeli history, involving funds from several other countries.

Investigators say employees helped customers move money without reporting the transfers.

We have 45 customers of whom we have very serious suspicions of wrongdoing Police spokesman Gil Kleiman

Of those taken into custody, two have been put under house arrest while eight had their detention orders extended in court.

Police spokesman Gil Kleiman confirmed its operation had moved on to the company's client base.

"Last night we questioned and arrested our first customer and today we will start with more customers," he said.

"We have 45 customers of whom we have very serious suspicions of wrongdoing," he added.

Accounts frozen

More than $375m has been frozen and police are examining more than 80 bank accounts linked to 170 customers.

Police said funds had passed through the bank from many countries but named only France.

All the employees arrested worked at a central Tel Aviv branch of Bank Hapoalim.

After introducing anti money-laundering legislation, Israel was removed from an OECD money-laundering blacklist in 2002.

In a statement the bank said it had ordered its employees to co-operate fully with the investigation and said it had taken several measures to prevent funds being laundering through the bank.

One of those questioned was former chief executive Eli Yones although police said he was not considered a suspect.