Israeli Prime Minister Benjamin Netanyahu has lashed out at the country's chief of police ahead of an expected announcement concerning a corruption probe into the long-standing leader.

Police Chief Roni Alsheikh said on Wednesday that "powerful figures" had hired people to "sniff around" the detectives investigating Netanyahu.

Netanyahu responded in a Facebook post, saying Alsheikh's comment was a "bizarre and false suggestion" and that "a great shadow" was cast on the investigation.

Netanyahu has repeatedly denied any wrongdoing throughout the corruption probe.

Israel media say police are expected to submit their recommendations concerning the investigation to the attorney general as early as next week.

Police officials declined comment.

Channel 2 TV claims a police document emerged indicating there's enough evidence to indict Netanyahu but that no decisions have been made.