"(Alternatively) Mr Snowden would doubtless be safe-but-sorry in North Korea and might find refuge in Russia," Mr Robertson told AAP in a statement.
"A more pleasant environment would be New Zealand where he could join Kim Dotcom in resisting extradition."
Dotcom is wanted in the US on internet copyright charges relating to his file-sharing website Megaupload which was shut down after he was arrested during a raid on his mansion north of Auckland in early 2012.
The New Zealand resident previously spent the better part of a decade in Hong Kong.
Mr Robertson says while New Zealand is one option it would be "really interesting" if Snowden travelled to Europe and relied on Article 10 of the European Convention on Human Rights which protects free speech.
"The European Court of Human Rights ... could rule that Mr Snowden cannot be extradited to serve many years in an American supermax prison for revealing that the US subjects Europeans to an intense surveillance it could not by law impose on Americans," he said.
US President Barack Obama's spy chief has described the surveillance leaks as gravely damaging to security and the US Justice Department has launched a probe that could lead to charges.
- AAP