More than two years of snooping has not yet established whether the sale of Motukawaiti Island in the Cavalli Islands group was legal.
And the Overseas Investment Office (OIO), which is carrying out the investigation, is still not disclosing details of the probe.
Explaining yesterday what was going on, investment office manager Annelies McClure repeated what she had told the Advocate in 2010 when asked about the sale of Motukawaiti.
"The OIO is continuing its investigation into the purchase of the island in order to confirm compliance with the Overseas Investment Act 2005," she said.
"As this is a very complex investigation involving a number of individuals and organisations it is not possible at this point to place a timeframe on when the investigation is expected to be concluded.
"We are unable to provide further detail or information as this could impede the OIO's ongoing investigation."
Labour MP David Parker said the long, mysterious investigation "beggars belief" and it was time Land Information NZ brought the inquiry to a head.
"What is it they are investigating and why is it taking so long?" he asked.
The 37ha island in three titles was transferred from the Motukawaiti Island Trustee Company to St Morris NZ in August 2010. The sole director of St Morris NZ is Wenning Han, of Auckland.
It is understood more than $11 million was paid for the property.
A luxury boutique guest house on the island was empty and deteriorating, former Maori Affairs Minister Dover Samuels, of Matauri Bay, said: "No one is permanently living there."
Mr Samuels said pa had been on the Cavallis in pre-European times and local Ngati Kura hapu members had moved old human bones to the mainland for burial after storms exposed them on beaches.
"Otago University experts told us some of the skeletons were over 800 years old."
Motokawaiti's new owners had been invited to the Matauri Bay marae to learn how significant the Cavallis were to Ngati Kura, but had not been seen since.
"People come and go [to Motukawaiti] but we are dealing with phantoms most of the time. No one has contacted us," he said.