Prime Minister John Key is asking the media if it really wants to see journalists' communications with MPs made public.
That could be part of a potential Privileges Committee investigation into United Future MP Peter Dunne, who resigned as a minister on Friday after refusing to comply with an inquiry into who leaked a report into the Government Communications Security Bureau.
The week before, he flatly denied being the source when confronted by New Zealand First leader Winston Peters at a select committee. Misleading a committee is akin to misleading Parliament.
Mr Dunne is refusing to fully disclose dozens of emails in which he discussed the possibility of leaking the report to a Fairfax reporter, but maintains he did not go through with it.
The Labour Party has lodged a privileges complaint.
Mr Key said the media should ask itself whether it wants journalists' communications with MPs laid bare when it has been very averse to such disclosures in the past.