The National Party has accused the government of forcing officials working on the $3 billion Provincial Growth Fund to cut corners to meet unrealistic deadlines.
Its regional development spokesman Paul Goldsmith said an internal review released late yesterday on the Renew Energy fiasco was "alarming".
It showed officials failed to do any due diligence on the people behind a proposed waste-to-energy scheme before recommending a $350,000 taxpayer funded feasibility study.
Regional Development Minister Shane Jones put the money on hold in February after RNZ told him its chief executive Gerard Gallagher had been referred to the Serious Fraud Office.
Mr Goldsmith said officials were under pressure from a government wanting "quick wins" for political gain.
"It's not hard to spend $3 billion but it's quite hard to spend $3 billion effectively, and to do that you have to have proper systems in place and clear procedures.
"And what we're seeing doesn't fill us with confidence at all."
Mr Jones said he was "disappointed by the lack of checks and balances" but he had confidence in the Provincial Development Unit.
"The scaling up process was a steep learning curve and I thank Nigel [Bickle, the head of the unit] and his team for their thorough review."