Katrina Casey, head of sector enablement and support for the Ministry of Education, said Mr Hourigan's latest appointment had been made "after a unanimous request from the school's board of trustees".
"We have been working with the school for some time, but believe this higher level of support is needed at this time.
"We appointed commissioner Jack Hourigan on March 31 as a result of the risk to the operation of the school ... By picking up the role of governing the school, the commissioner is responsible for ensuring students get a good education, that resources are being used properly, and for overseeing the management of the school. The commissioner also picks up the board's responsibilities as the employer of all staff."
Mr Hourigan's appointment was made under Section 78N(2) of the Education Act 1989, and represents the final stage of an intervention process by the ministry established under statute.
Kea Street Specialist School's latest ERO assessment, dated February 12, flags a number of ongoing governance issues at the school.
While the report observes a commitment from trustees to "ongoing school improvement," it highlights problems, including concerns about "key aspects of school leadership" from staff and the lack of a signed annual performance agreement. The report concludes with the recommendation of continued intervention due to ongoing issues with management.
Ms Casey said commissioners had "a track record of successfully resolving difficult issues," and part of Mr Hourigan's brief would be to address all the issues identified by ERO.
According to Ms Casey, in the vast majority of cases schools return to governance within two years, and all interventions are reviewed within 12 months.
"We've got full confidence that Mr Hourigan, a retired principal, has the skills needed to get Kea Street school back on track," she said.
Kea Street Specialist School's principal, Sherie Collins, could not be reached for comment, and it was unclear at the time of writing whether parents with children at the school had been informed of the appointment.
Kea Street Specialist School provides education for students aged 5 to 21 with intellectual and physical disabilities, from the greater Rotorua and Taupo area.