New Zealand First leader Winston Peters is defending his use of leaked information to pursue former government minister Peter Dunne.
Mr Dunne resigned as a minister on Friday after refusing to co-operate with an inquiry into the leaking of a report on the Government Communications Security Bureau.
Mr Dunne said emails between himself and a Fairfax Media reporter show that he was not the source of the leak but has refused to release them.
Mr Peters said he is aware of five sets of electronic records showing that Mr Dunne was responsible for leaking not just the report but other information to Fairfax.
He said his sources were justified in providing him with information because the leak related to national security and in that context they acted legally and ethically.