The police are investing a potential leak in parliament which led to secret information about national security issues being leaked to a journalist, the Telegraaf says on Tuesday.

The paper says a number of party leaders have been questioned and their phone numbers compared with that of a reporter for the NRC newspaper. The leak focuses on the government’s denial in 2014 that details about 1.8 million phone calls and internet messages made in the Netherlands were passed to the US security services.

Home affairs minister Ronald Plasterk first denied the information had been sent to the US but was later forced to backtrack.

It emerged later that Plasterk had told a parliamentary committee which deals with confidential security issues about the information agreement with the US. Later the NRC reported that the committee had been briefed, and Halbe Zijlstra, leader of the ruling VVD, made a formal police complaint about the leak.

The Telegraaf says the information has not turned up enough evidence to proceed with the complaint and senior public prosecution department officials are now deciding what to do next.

The paper says some party leaders are now concerned that their phones in the parliamentary complex are being tapped by the security services.