"We know that there are areas where we need to keep lifting our game and we are committed to doing that," she said.
Ardern admitted mistakes in the past, especially through uncertainty created in the early days of the outbreak, and said there was no doubt it has been a difficult process.
But she is now confident that the systems will be quicker and more improved with the certainty that will follow yesterday's eradication decision.
O'Connor this morning announced the appointment of a science adviser, 50 more staff for MPI and a new field headquarters as the Government ramps up its response to the outbreak.
He accepted that it's been "a big challenge" for MPI but says they are doing "everything we can to help the farmers involved".
"This is a brand-new challenge for us. We just need to make sure we learn from the experiences we are having," he said.
Ardern and O'Connor said they are no closer to finding out where the disease originated.
Claims it first came to New Zealand in 2014 is being investigated, O'Connor said, but added: "We firmly believe it was after 2015. We will be pursuing any claims farmers make but we have to investigate them in a scientific way."
There is no time frame for when the investigation will be completed, he said.
A comprehensive review of the Biosecurity Act 1993 will follow once the outbreak is under control, the ministers said, to make sure it is "agile enough and fit for purpose", Ardern said.
But she stressed it's not yet known how it came to be in the country, and where it came in, illegally or not.
"Everyone wants to know – how did this get here and did someone break the law in the process of bringing it here. That's a very good question we want to know the answer to, and MPI is working on it."
Given that it had only been Norway and New Zealand that previously didn't have M. Bovis, then it should have "no impact" on New Zealand's international reputation, she added.
