Labour Party leader Phil Goff says the Prime Minister is confused about Labour's proposed changes to foreign investment rules.
Mr Goff says a future Labour Government would effectively end sales of farm land to foreign investors.
John Key says the 2005 Act passed by Labour when it was in power actually spells out everything Mr Goff proposes.
But Phil Goff says Mr Key is absolutely wrong. The measures will be quite new and different, he says, and will mean farm land sales will be the exception, not the norm.
Meanwhile, the Green Party says if Labour is serious about tightening up on foreign ownership of New Zealand land, it should adopt the Greens policy.
Greens co-leader Russel Norman says Labour's policy is unclear and is unlikely to make any difference.
He says the Green Party policy of any land more than 5ha in size staying in New Zealand ownership would be a clearly defined rule.