In the file held by the Herald, hundreds of messages sent from people working on ministerial or government computers are linked to the servers and IP addresses from which they were posted. The file links those details with email addresses - including Mr Bryant's.
Asked if he had posted to Whale Oil, Mr Bryant initially said: "I don't know."
When asked if he used the name "Former Hack" to do so, he said: "Nicky Hager said I was the person who posted as that."
Told of the new information, Mr Bryant said: "What I will say is I stopped commenting around that time. They were about the only comments I made on that blog."
At the time of the comments, Mr Bryant worked for former minister Phil Heatley.
Mr Hager's book links Mr Bryant to another anonymous name - but the Herald has found the email account linked to messages from the person is actually registered in the name of yet another ministerial staff member.
A spokesman for Internal Affairs refused to comment on individual staff members. He said "appropriate action" would be taken against a staff member who acted inappropriately.
Slater did not return calls. He did send an email saying: "Time for all your emails to come out Fish."
Other developments
• Rodney MP Mark Mitchell has told the Weekend Herald he is considering suing Nicky Hager over assertions in the book that he would not have won his electorate in 2011 without a dirty tricks campaign from Slater and political adviser Simon Lusk.
• Prime Minister John Key said yesterday he was happy to provide his phone records and give evidence under oath to an inquiry by the spy watchdog into the handling of an Official Information Act release by the SIS to blogger Cameron Slater.
• The Whale Oil site boasted its largest number of visitors in the wake of the book's publication - although others have questioned the validity of the figures. The site also reported Pak N Save's advertising agency had set up an "exclusion" to make sure its adverts no longer appear on the blog.