The Prime Minister's office says the Government is investigating whether a Security Intelligence Service (SIS) officer leaked information to the media over spying allegations.
Both the police and the SIS carried out investigations into the activities of three Israelis who died in the Christchurch earthquake.
The Government confirmed on Wednesday it had found no evidence to suggest a link between the group and Israeli intelligence.
A spokesperson for the Prime Minister says the SIS is investigating a suggestion that information was provided to the media by an SIS officer.
A State Services Commission spokesperson says it is not involved in the hunt for the source.