The Prime Minister says it's clear an email breaching Cabinet confidentiality made its way through his predecessor's office.
Stuart Nash has been sacked after emailing two donors in March 2020, detailing secret Cabinet discussions.
It's now come to light the email was considered and ruled out of the scope of an Official Information Act request in 2021.
Chris Hipkins says Jacinda Ardern did not know about it, but it clearly went through her office.
National wants to know why the leak took so long to surface publicly.
Morning Report's requests to speak to both Chris Hipkins and Stuart Nash were declined, but Otago University associate professor of law Edward Willis was willing to talk.
He spoke to Corin Dann.
