The Ministry of Maori Development, Te Puni Kokiri, has spent nearly $3 million on contractors already this year.
The numbers have risen sharply despite the chief executive's pledge in 2013 to reduce spending on consultants.
Last month the organisation, which employs about 250 people, spent $669,000 on contractors and in June it was $487,000, bringing the total already this year to nearly $3 million.
The Minister in charge of Te Puni Kokiri, Te Ururoa Flavell, said he was not concerned and backed chief executive Michelle Hippolite.
"You'll have to ask the chief executive about that. It's an operational matter. While I've been having a look at it, in the end it's the operational detail that the chief executive needs to answer," Mr Flavell said.
Twenty-one staff members have left Te Puni Kokiri during the past 10 months, including one of its deputy chief executives.
Documents handed to Radio New Zealand show that as permanent staff left the bill for contractors rose swiftly.
Mr Flavell said that could be expected after a restructure.
"I talk to them regularly but, like I say, I'm comfortable with what she's attempting to do," he said.
"It's been a time of change and transition. These sorts of things come with staff leaving, some coming on, some inability to fill some positions...in the transition to a new structure. So in the end I think it's just par for the course of the change in the organisation."
Mr Flavell said he had no reason to be concerned with the numbers leaving but admitted it was not the first he had heard of the issue.
"I've been getting questions about that from a number of people and I've responded to those questions to say it is an operational detail and I can't give, you know, all the specifics about what's happened within the organisation."
Ms Hippolite restructured Te Puni Kokiri in 2013, saying it would help reduce the amount of spending on outside consultants.
She did not respond to calls from Radio New Zealand.