Tauranga-based airline Sunair Aviation has been grounded by the Civil Aviation Authority for the second time in nine months.
The authority suspended Sunair's Air Operator Certificate, along with the Certificate of Airworthiness for the Sun Air fleet, on September 8.
A spokeswoman for the authority said the action would ground the Sunair fleet and suspend all Sunair flight operations for an initial 10-day period.
"An investigation into the company by the CAA is continuing," she said.
When asked exactly what they were investigating, what concerns prompted the investigation and when it began, the spokeswoman said the authority could not comment on the investigation.