Mr Peters said: "The owners are losing their livelihood despite appeals to the Overseas Investment Commission and their National Member of Parliament.
"The Prime Minister needs to explain why he, as Minister of Tourism, went missing on this occasion."
He said the sale of the 35,000 acre (14,164ha) station was ticked off on the grounds that it would create and retain jobs.
"Clearly, on this count, the company has broken its word. Sixteen jobs will be lost."
Coast Range NZ bought a 25 per cent stake in Flock Hill in 2008, and was given OIO approval to increase its holding to 100 per cent in 2010.
Mr Key said this afternoon that the OIO only approved applications which had "substantial and identifiable benefits".
He was certain the benefit of foreign investment would outweigh the potential job losses at the tour company.
"With the greatest of respect you're losing the plot if you think 16 jobs there can't be measured against all of the other benefits of foreign investment."
He added: "The amount of land being sold foreigners is small, its discreet, but from time to time it happens."
Mr Cosgrove said Mr Key's response to the company's potential collapse was "arrogance of the highest order".
"The Tourism Minister should not gloat over the loss of a major tourism operation and 16 jobs. He should apologise to High Country Explorer Tours head Rod Bennett and those people set to lose their jobs.
"There is no benefit in this sale to New Zealand apart from the seller getting rich and the foreign buyer getting 35,000 acres of Kiwi land."
In an email to ministers on September 12, High Country Explorer Tours managing director Rodney Bennett appealed for an urgent resolution, saying he had 62 tours booked for the 2014-15 season.
Labour and New Zealand First have promised to make it more difficult for sensitive land to be sold into foreign hands if elected.
