Foreigners who have bought land in New Zealand and are found to have lied on their application should forfeit the asset, NZ First says.
Deputy leader Ron Mark says the Overseas Investment Office must tell buyers to present straightforward applications with their background clearly detailed and authenticated.
"Instead of delivering a strong warning, the government has announced changes to the OIO that will do nothing to improve scrutiny and weed out foreign rogues who want to buy our land," he said.
"Too many individuals are deliberately using complex company structures in their applications, so intricate the OIO has admitted processing takes time."
The Government yesterday said the OIO was going to increase its fees by more than 160 percent in some cases as it gets ready to hire more staff and speed up its processes.
The office vets applications from foreigners who want to buy land in New Zealand, and it's in the dogbox because it approved the sale of the 1320ha Onetai Station in Taranaki to two brothers who had criminal convictions in Argentina.
The approval is being reviewed.
Prime Minister John Key said on Wednesday he still had confidence in the office, but opposition parties don't and they want it to review every approval it's granted that might have allowed "people of poor character" to buy land
Labour's David Cunliffe last week revealed the identities of the brothers who were allowed to buy the station.
They were Rafael and Federico Grozovsky, and they bought the station for $6 million in 2014.
Mr Cunliffe also revealed that in 2012 they were convicted because their Argentinian tannery leaked chemicals into a river.
Mr Cunliffe says there are other cases where he believes approvals were wrongly granted.