The Solicitor-General provides advice to the government on legal matters.
Mr Morrison said he had not received this advice from his office.
"He is entitled to his opinion on this, but that is not the advice I have been provided at any time during the course of managing this matter," he said.
Mr Morrison said Mr Porter was an "innocent man" under Australia's legal system and a "fine" attorney-general and industrial relations minister.
“He is an innocent man under our law,” Mr Morrison said.
"To suggest there should be some different treatment applied to him, based on what had been allegations that the police have closed the matter on, I think it would be grossly inappropriate to take actions against him on that basis."
Mr Morrison has dismissed calls for an independent inquiry into the allegations against Mr Porter saying the process would be contrary to the "rule of law".
However, some legal experts have questioned the basis of Mr Morrison's justification for not holding such an investigation given the circumstances surrounding the allegations.
The South Australian coroner is investigating the circumstances surrounding the woman's death and is currently considering whether to conduct an inquest.
Labor, the Greens, independent politicians and former prime ministers Malcolm Turnbull and Kevin Rudd have supported calls for an independent inquiry to go ahead.
Mr Porter - who is currently on stress leave - does not intend to step aside from his position and warned that he has become a victim of trial-by-media.
He has also raised concerns that the process of an independent inquiry would force him to "disprove something" that he claims "didn't happen".
Mr Morrison said he "wouldn't consider moving" Mr Porter aside from his role of attorney-general.