Industry lobby group Federated Farmers said it welcomed what it saw as an honest apology.
"This official acknowledgement that mistakes have been made is important, as it signals there is a willingness to learn from what has happened in the past and to improve the response going forward," its national president, Katie Milne, said.
"The backlog of work brought about by under-resourcing and deficiencies in management and training has caused a lot of unnecessary angst and distress for our framing families."
It was now essential the problems were fixed as quickly as possible, she said.
The first of the reports released this week, from MPI's chief science advisor, John Roche, concluded the backlog of properties needing to be checked rose to about 1400 in April this year and that the delays may have contributed to the spread of the disease.
About 300 reported cases were considered urgent by the Ministry and extra resources were put into getting them sorted.
Roche's found the Disease Management Database System being used was not up to scratch for the scale of the operation and also pointed to problems in communications about workloads.
"Farmers, veterinarians, and response field personnel claim that they reported to the National Control Centre a failure of the response to contact farms of interest from last spring, but believe their concerns were not given due consideration," he said.
The second report, independently commissioned by DairyNZ, found issues with staffing, training, management and systems had led to delays of up to seven months for some farmers.
Biosecurity and Agriculture Minister Damien O'Connor said eradication was still viable and the programme was only in its first year of ten.
"The backlog was certainly disappointing but the advice from experts is that they don't believe it has impacted our chances of successfully eradicating M. bovis," he said.
"Mistakes have certainly been made. In a perfect world there wouldn't have been, but farmers and Mycoplasma bovis response staff are working in difficult and stressful situations ... The programme is being improved every step of the way."
More than 100,500 cows have so far been slaughtered and 176 farms confirmed infected in what is the largest eradication programme in New Zealand's history. About 600 more properties are being monitored.
The effort has cost the Government $234 million so far, including compensation to farmers.
The bacterial disease - which was first confirmed to be in the country in July 2017 and causes pneumonia, arthritis and abortions in cattle - is found almost everywhere overseas. A successful eradication would be a world-first.
It poses no risk to humans or food but is considered an animal welfare issue.