Israel's Attorney General Avichai Mandelblit said on Sunday he had ordered an "examination" into an unspecified affair involving Prime Minister Benjamin Netanyahu, after weeks of media speculation and rumours.
"After receiving information on matters pertaining, among others, to the prime minister," Mandelblit met police and justice officials, after which he decided "to order an examination into the matter," a justice ministry statement read.
"We stress that this is an examination and not a criminal investigation into the prime minister," it read.
The ministry provided no further details, but media said the suspicions involved a money transfer.
A spokesman for Netanyahu said that "as in all of the previous cases" of suspicions against the premier, "this will contain nothing too -- because there's nothing there".
Netanyahu last month acknowledged receiving money from French tycoon Arnaud Mimran, who was on Thursday sentenced to eight years in prison over a scam amounting to 283 million euros involving the trade of carbon emissions permits and the taxes on them.
The allegations against Netanyahu are the latest focused on his spending.
In May, the Israeli state comptroller issued a critical report about Netanyahu's foreign trips, some with his wife and children, between 2003 and 2005 when he was finance minister.