Blogger Cameron Slater should be able to claim the mantle "journalist" to protect his sources in a defamation case, the High Court at Auckland has heard.
But defamation expert Julian Miles, QC, said if the blogger did then refuse to reveal his sources he would struggle to defend claims his blog posts about a businessman were "honest opinion".
Mr Miles was called to the High Court to offer expert advice in a defamation action against Slater - the first case in New Zealand in which the definition of "journalist" has been a key issue.
Former Hell Pizza executive Matt Blomfield has alleged Slater defamed him in a string of posts on his Whale Oil website.