The Ministry for Primary Industries says it has been successful at protecting New Zealand from a number of biosecurity breaches but there is room for improvement.
An Auditor-General's report released on Thursday identifies weaknesses in readiness to deal with a biosecurity outbreak such as foot and mouth disease.
The report says the ministry's planning is unrealistic and undeliverable.
A biosecurity consultant for the World Bank, Roger Morris, believes the ministry has shifted its emphasis from protecting New Zealand against threats in favour of focusing on building international trade.
However ministry Deputy Director-General and head of biosecurity Andrew Coleman said its handling of the Queensland fruit fly discovery in Auckland last year proves it is capable of protecting the country.
Mr Coleman told Radio New Zealand's Morning Report programme the ministry successfully deals with 30 to 40 biosecurity incursions each year, but conceded there are areas for improvement.
Warning of legal action unless biosecurity gaps plugged
New Zealand First leader Winston Peters said the country is dicing with economic disaster because the losses from foot and mouth disease would be massive.
He said the Government is also opening itself to legal action for failing in its duty of care.
The Green Party said biosecurity has been done cheaply and the Government must dip into its pockets to reverse the situation.
Primary Industries Minister Nathan Guy said continuing to improve biosecurity is his top priority and he will carefully consider the report's findings.
Mr Guy said the Government is conscious of how important it is to protect the border and believes a large amount of work has gone into planning for foot and mouth disease.