A principal struck off for sleeping naked with a student kept getting contracts from the Ministry of Education for more than two years after officials became aware he was being investigated.
Last month it was revealed Uenuku Fairhall, the former principal of Te Kura o Te Koutu in Rotorua, had his registration cancelled and was censured by the Teaching Council's Disciplinary Tribunal Council in 2018.
Fairhall was investigated after being accused of sleeping naked with a student during a school trip to Mexico in 2017 and council described his actions as "despicable".
The Ministry of Education has confirmed it found out about the investigation in 2017, but kept giving Fairhall's sole-charge company, Tarapō, contracts until August this year.
The company was contracted six times at a total bill of $500,000 to provide specialist Maori Medium Services from February, 2016.
Five of those were from after the Ministry was told Fairhall had resigned, although the ministry was unable to confirm their value on Thursday.
In a statement, Secretary for Education Iona Holsted said the contracts should not have been given out.
"We should not have continued to contract with Tarapō after serious allegations about Mr Fairhall's conduct were raised in 2017," she said.
"Decisions about contracting are an operational matter and the accountability for that sits with me as the chief executive."
Holsted said due to suppressions, the Ministry only became aware Fairhall had been struck off mid-August, when he was publicly named.
"I also wish to be clear that I have received assurances that Mr Fairhall has not engaged with any children or young person as part of the contract work he has done for us," she said.
"As soon as the Teacher's Council's finding was released, we proceeded to terminate the one remaining contract we had with Tarapō."
Holsted said she had also apologised to Education Minister Chris Hipkins for failing to meet the standards and for not having briefed him properly on the matter.
A spokesman for the minister said he accepted it had not been intentional.
"The Minister has accepted the Secretary's apology and welcomes her efforts to tighten up processes in this area," he said.
The Ministry of Education has launched a full review of "every aspect of the procurement process for these contracts" and called in outside auditors to look at similar contracts.
The Ministry previously defended contracting Fairhall's company, saying it had not worked directly with Fairhall.
However, in a statement this week a spokeswoman confirmed it had, in fact, been in touch with him.
"We have now found emails over the three-and-a-half year period that show that we did communicate with Mr Fairhall about the Māori medium services Tarapō Ltd were providing," she said.
National Party MP Nikki Kaye is calling for an independent investigation.
"The Minister has taken a very relaxed approach, stating he was satisfied the ministry had acted appropriately, and quickly enough, following the announcement of the Teaching Council decision," she said.
"An independent investigation is needed to look into the ministry's processes given the changing nature of their statements and their systems around contracting people being investigated for serious allegations."
The Ministry said it had also removed three videos posted in 2010 of Fairhall teaching haka after the council decision was made public, but that the videos had been taken down and reuploaded during an "administrative refresh" in 2018.
"Regardless of why this occurred it is insensitive to the children involved in this case and shows a sloppy approach," Kaye said.