Mr Peters said the island's sale, and the tardy investigation, highlighted the need to "fence off" New Zealand from foreign speculators.
The fact that an island believed to have been bought illegally could then be re-sold showed how cavalier the Government was about land sales, and how eager it was to kowtow to foreign interests regardless of merit.
It also raised questions about the competence and lack of accountability of the OIO and Land Information New Zealand.
"Why has the OIO not been held to account for its tardiness around the 'sale', or its failure to use all its powers to ensure that New Zealand law is complied with? ... A first-year law office clerk could have resolved this in a matter of a few months. Why would it have taken two people in the OIO 48 months to not get to the truth?"
The reported sale price of $11.5 million four years ago and the current asking price of $30 million showed how "rampant speculation" was forcing land out of New Zealanders' reach, Mr Peters added.
LINZ's general manager of crown property and investment, Brian Usherwood, put the length of the investigation done to its complexity.
"This is a very complex investigation involving a number of individuals and organisations," Mr Usherwood said.