The Overseas Investment Office (OIO) says it has issued a formal warning to Ceol & Muir and its owners, Argentinian brothers Rafael and Federico Grozovsky, for failing to provide complete and accurate information when they applied to buy Onetai Station in 2013.

OIO Deputy Chief Executive Lesley Haines says the warning will be taken into account in all future information that Ceol & Muir provide to the OIO, including during its ongoing monitoring of their consent.

"There were two issues with the information they provided us in their application: the ownership of Ceol & Muir and not telling us about prosecution proceedings in Argentina," she says.

"However, we do not believe there is a need to take further action at this point. This is because while the application contained an inaccurate statement – that Ceol & Muir was a trustee for Grozovsky family interests – the OIO was not misled on the ultimate ownership and control of the investment."

Ms Haines says the OIO was aware that the Grozovsky brothers had been charged for alleged pollution offrences in Argentina when Ceol & Muir applied for consent. However, the brothers have not been found guilty of any criminal offences.

"We are monitoring closely the court proceedings in Argentina. If the Grozovsky brothers are found guilty, we will consider the outcome and they could be made to sell Onetai Station."

Ceol & Muir purchased Onetai Station in Awakino, north of Taranaki in 2014. The OIO investigated the company and its owners after the leaked Panama Papers showed a connection with Panamanian law firm Mossack Fonseca, which acted as an incorporation agent for Ceol & Muir.