Labour using law it called 'dreadful' to target farmers - Collins

National is condemning changes to the National Animal Identification and Tracking Act it "reluctantly" voted in favour of on Thursday night.

The changes will give Ministry for Primary Industries (MPI) inspectors the right to "lawfully obtain information where non-compliance is an issue", according to the Government, to assist in the fight against Mycoplasma bovis.

"MPI will be able to turn up to farmers' properties without getting a warrant and seize anything they want, unannounced and without cause," said National agriculture spokesman Nathan Guy.

"Agriculture Minister Damien O'Connor has had months to introduce this Bill into Parliament, but instead he expanded wide-ranging search powers under urgency."

Mr O'Connor says the changes "go no further than powers that already exist under other Acts", specifically the Search and Surveillance Act.

National MP Judith Collins was Minister of Justice when the Search and Surveillance Act was made law. She told The AM Show Labour, NZ First and Green voters were "marching in the streets" against it.

"I remember the Greens and NZ First and Labour all voted against it - said it was a dreadful thing."

She said the changes, while aimed at non-cooperating farmers, won't work unless the entire sector is on board.

"These are their homes as well as their businesses. You're never going to have a system that works well unless the farmers want it to work well, understand it and trust the people.

"This whole treating farmers as though they're the bad people, even though we know that this has happened and everything else, many of the farmers are actually victims of it. I think you need to be a little bit careful and get people's trust."

Labour MP Michael Wood, appearing on The AM Show alongside Ms Collins, said the changes wouldn't be needed if all farmers could be trusted.

"We've had a small number of farmers who haven't behaved well around this stuff, and that's put the entire sector at risk - potentially $800 million we're going to need to clean this up. It's a power that will be used with quite a bit of discretion - it's not going to be every farmer," he said, adding that good farmers won't have anything to worry about.

"Why are MPI going to bust in on people without a very, very good reason? M bovis is ravaging the sector. We're spending a huge amount of money to clean it up. It's a huge risk to the economy and we've got to be able to deal with it."

Industry representative Beef and Lamb NZ welcomed the changes.

"Those farmers who work hard to comply with [the] requirements have increasingly been asking for stronger penalties and compliance actions against those who put the industry at risk and this will give them confidence that some action is being taken," said general manager policy and advocacy Dave Harrison.

National proposed a few amendments to the Bill, including preventing MPI staff from stepping foot on a farm without a warrant and "reasonable cause", but Mr Guy says they were turned down.

"However, National did successfully move an amendment that requires the Minister to report to Parliament next year on how these expanded powers are being used. We will await this review with a great deal of interest."