The public prosecutor is looking into possible breaches of the country's criminal code by government officials, regulators and executives of the two banks that agreed to carry out an emergency merger last month to avert a collapse in the country's financial system.

The office said in a statement that there were "numerous events hovering around Credit Suisse" that called for the investigation to be opened and required to be analyzed "to determine whether there are any criminal offenses that could fall within the (public prosecutor's) jurisdiction."

"The Public Prosecutor's Office wants to proactively fulfill its mandate and responsibility to contribute to the integrity of the Swiss financial center and for this purpose has established a monitoring system that enables it to take prompt action on any issues that fall under its responsibility," the statement added.

The office did not indicate any specific aspects of the merger agreement that it might look into or how long the investigation might take.

Credit Suisse and UBS did not immediately respond to requests for comment.

Last month, UBS said it would take over rival Credit Suisse for 3 billion Swiss francs ($3.3 billion) in a deal overseen by the Swiss central bank, government and the country's banking regulator.

Sources told Reuters that UBS is trying to close the deal by the end of April.

($1 = 0.9148 Swiss francs)