Ms Rebstock's suspect took the case to the High Court in an attempt to stop their name from being included in the report to the State Services Commissioner Iain Rennie, who commissioned it almost a year ago.
Jason McHerron, the lawyer representing the public servant, said there was no evidence that the documents had been distributed after they were scanned and photocopied.
He said the allegation that his client had been the leaker should not be repeated in a final report.
"Arguably that would render it a finding or opinion that was unreasonable in the administrative law sense."
But lawyer for the Attorney-General and Ms Rebstock, Una Jagose, argued it was reasonably open to Ms Rebstock to attribute what she had included in the draft report to each of the answers relied on in the interviews with the suspect.
Justice Dobson said it was reasonable for the employee to be concerned that publication of a report could damage their reputation if it concluded that they were responsible for the leak.
"For those interested, but at a superficial level, the linking of A's name with a report finding that unauthorised disclosure had occurred would likely attribute responsibility to [the public servant] on a `where there is smoke there is fire' basis."
He found that Ms Rebstock did not go beyond her terms of reference and would not exceed her jurisdiction if she completed a report that referred to a strong suspicion that the employee was responsible for leaking the Cabinet papers .
"If the intended audience for the completed report is confined to the commissioner, then in that context there has been no breach of the obligations to comply with the rules of natural justice in the extent of information provided to A."
But he said if there was an intention for the commissioner to publish the report then that would be contrary to natural justice and the disclosure that had so far been provided to the suspect was "inadequate".
In that case the report could not be presented until the suspect received more detailed information into Ms Rebstock's investigation, Justice Dobson said.