By Peter Wilson and Dave Williams
Labour's David Cunliffe says it's "absolutely unbelievable" the Overseas Investment Office allowed two men with criminal convictions to buy a Taranaki station.
The OIO yesterday admitted it blundered when it approved the application and has apologised to the government.
The brothers who bought the 1320ha Onetai Station for $6 million in 2014, Rafael and Federico Grozovsky, were convicted in 2012 in Argentina because their tannery leached chemicals into a river.
Land Information Minister Louise Upston says if they're found to have misled the OIO they could be forced to sell the station.
Mr Cunliffe last week revealed their identities and their conviction.
The OIO put them through its good character test in 2013, and they passed.
"It's absolutely unbelievable -- this is the government agency presiding over the sale of thousands and thousands of hectares of New Zealand land," Mr Cunliffe said in parliament.
"They've only turned down one application in the last five years -- they've approved 99.85 percent of farmland sales."
The application the OIO turned down was a Chinese bid for Lochinver Station.
"And that was only after weeks of public attention and ministerial intervention," Mr Cunliffe said.
The OIO says it failed to tell the land information minister it knew of the pollution incident when it recommended approving the sale.
"Relevant information was not passed on to government ministers. I have advised Land Information Minister Louise Upston of this situation and apologised," chief executive Peter Mersi said.
"I have also given her an assurance there will be no repeat of this situation in future."
Mr Mersi says the OIO is reviewing its process around assessing good character of foreign buyers after going over the case.
An independent review will also be carried out.