On the $26,592 for MCs Alison Mau and Marcus Akuhata-Brown, Little said it was important to have good people who could keep the dialogue going.
"I think they did an outstanding job. There were, as we expected there would be, moments of tension … and I think they were both, at the time they were doing the facilitating and MCing, they both managed that well and avoided what could have been a much more difficult situation. That reflected on their skills."
Little wrote to the Justice Secretary Andrew Bridgeman when he saw, part-way through the planning process, the number of contractors and consultants involved, to make sure it kept costs under control.
"I've asked them to review the issue of the expenditure of money and they've yet to come back to me about what their systems were in place to manage and control cost."
The letter said all significant expenditure decisions must be referred to the minister's office prior to being incurred.
National's justice spokesperson Mark Mitchell said the summit was a "talkfest that had no clear objectives and has shown no outcomes.
"The cost would be easier for taxpayers to swallow if they were getting value for money," he said.
Between 600 and 700 people within the justice sector attended the Porirua event which was held to look into ways to turn around New Zealand's high reoffending rate and rising prison population.