Immigration New Zealand's boss says it's unacceptable staff concerns were ignored.

The Public Service Commission's released its report on the Accredited Employer Work Visa scheme, which began after a whistle-blower alerted the Minister to a lack of checks and balances.

The review has found Immigration New Zealand should have done more to minimise migrant exploitation risk, when regulations loosened post-Covid.

MBIE Chief Executive Carolyn Tremain says concerns were first raised internally last April.

"What has occurred here is not good enough, and we're making sure that we have a two-way conversation with people about issues."

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