The daily Dnevnik reports on Monday that Austria had reported the case to the police.

Štemberger was at the helm of the national security and intelligence agency from March 2013 to November 2014. He had been appointed by the government of Alenka Bratušek.

During his term, a SOVA agent was allegedly ordered to make close contact with a female employee at the Austrian Embassy in Ljubljana to get inside information, Dnevnik says.

However, the mission failed, as the employee blew the agent's cover. Austria reported the incident to its police, who handed the case over to their Slovenian counterparts.

According to the paper, the Slovenian Specialised Office of the State Prosecutor is also acquainted with the case. But the office said their work concerning the security and intelligence agency was classified, so it could not comment.

The paper got a similar response from SOVA.

Prime Minister Miro Cerar's office meanwhile confirmed that the prime minister was acquainted with the proceedings launched by the Austrian authorities, but would not comment any further either since the proceedings are ongoing.

The paper's sources with close ties to the prime minister reportedly claim that the issue did not mar the good relations between Slovenia and Austria.

This was allegedly demonstrated by Austria's decisive support for Slovenia's view in the border arbitration scandal with Croatia that the arbitration process should continue.