Exclusive: More heat has gone on the Department of Labour, this time over its response to accusations of abuse on foreign fishing boats.
The revelations come a week after damning criticism of the department's handling of the Pike River mine disaster.
Following allegations last year of abuse at sea, the Labour Department had internal investigators take a look at crew conditions on foreign charter fishing vessels (FCVs).
But what they found fault with the department itself.
In an internal report obtained by the Green Party, the investigators found the department was aware "of at least some allegations of mistreatment of crews on FCVs since 2004, but have been unwilling or unable to fully resolve the problems in the industry."
"Those issues in themselves were not serious, but they were not addressed in the way that they should have been addressed," said Peter Elms, Immigration New Zealand general manager.
Green party co-leader Russel Norman says the issue never made it to a high enough level within the Department of Labour.
"That itself is a problem and I think it shows a failing by the Department of Labour to protect these workers," Norman said.
Despite allegations of physical abuse and slave wages, the department found there was insufficient evidence to charge the ships' operators.
But its internal investigation says a lack of action by the department in the past had allowed the situation to deteriorate.
"We weren't getting allegations of mistreatment on that scale prior to 2011. So whether that mistreatment was going on way before that time, we don't know," said Elms.
It is another blow for the Department of Labour which has been criticised for its role in the failure to prevent the deaths of 29 miners at the Pike River mine two years ago.
Norman said: "When you put the Pike disaster alongside the disaster really for the people involved in the foreign charter vessels, then together it's very clear that the Department of Labour wasn't doing its job properly and that we need an independent agency that is focused on protecting workers."
The Government has not committed to setting up an independent agency in the wake of the Pike River disaster.
Acting Labour Minister Chris Finlayson says he will receive advice on it in the next few months.