"What the Government's role is, is to determine whether the Overseas Investment Office followed the law properly."
In the last 18 months there were 72 sales of farms to foreigners and those 72 purchases met the conditions set out in the Overseas Investment Act.
Mr Key made his comments to reporters after delivering his state of the nation speech in Waitakere.
He said Land Information Minister Maurice Williamson and Associate Finance Minister Jonathan Coleman were looking at whether the Pengxin bid met the rules.
"If it does, they have no grounds to turn it down because if they do turn it down, then they'd be subject to judicial review and they would almost certainly loose."
"Public opinion is not a test. "
The test was whether it met the requirements under the law.
Mr Key also pointed to the Free Trade Agreement with China negotiated by the former Labour Government that contained a clause known as the Most Favoured Nation status.
That meant Chinese investment in New Zealand could not be treated differently to any other country.
Asked if he would have a problem with state-owned Landcorp managing the farms, as in part of the Pengxin bid, Mr Key said "I personally wouldn't, no."
He also said that neither the Chinese Embassy nor the Chinese Government had raised the Most Favoured Nation clause issue with him or his colleagues and no assurances had been given to them on the bid.
Mr Key said that the reason the bid - lodged in April last year - had taken so long was because "on numerous occasions, ministers have asked the Overseas Investment Office to go back and get further information."