One USAR worker even avoided security to run onto the runway and get onto the aircraft to join colleagues.
He was found and thrown off the plane, resulting in further delays with repeated head counts.
Flight Lieutenant Kylie Upton said it was a serious security breach with serious safety implications.
It was not reported because it would have caused even more delays, she said.
USAR, a unit made up of firefighters, dog handlers, communications experts, engineers, doctors and paramedics which specialises in finding and recovering people in dangerous situations, deny the incident ever occurred.
Flight Lieutenant Upton was speaking on the 10th day of a coroner's inquest into the deaths of Dr Tamara Cvetanova of Serbia, Cheng Mai of China, Japan's Rika Hyuga and Jessie Redouble, Emmabelle Anoba, Ezra Medalle, Reah Sumalpong and Mary Amantillo, all from the Philippines.
All were students at King's Education School for English Language on the CTV Building's third floor and survived the collapse but could not be rescued from the wreckage.
Flight Lieutenant Upton said it was critical for the RNZAF to know who it was carrying and what was on board.
She also said the planes needed to be weighted and balanced correctly before taking to the skies.
As the delays dragged on, Auckland USAR leader Murray Binning admitted becoming "very angry'' and frustrated, especially when he was told not all of his 15 tonnes of equipment could be transported.
He told the inquest that New Zealand Defence Force officials had earlier told him there would be "no problems'' with getting his kit down south.
St John staff and equipment were also on the flight.
Flight Lieutenant Upton said no training had been done with USAR previously to ensure they know what requirements for flight safety the RNZAF had.
Pre-loaded and sealed pallets could possibly be used in the future, as was done with other agencies.
Earlier, the inquest heard that expert rescuers had to receive frantic coaching on how to use high-tech listening equipment to find survivors buried in the collapsed CTV Building debris.
A USAR unit from Palmerston North arrived at the disaster site 12 hours after the six-storey office block came down in the magnitude-6.3 tremor.
But as they piled onto the rubble to find survivors, USAR technician Duncan Henry was stunned that his colleagues didn't know how to use 'delsar' listening gear.
He became "frustrated'' that he had to explain how the kit worked and where to put its ultra-sensitive sensors.
The sensors were put on steel beams and Mr Henry listened for any signs of life on the southwest corner of the building, but no positive sounds were heard.
USAR staff stayed on site until around 11am on February 23, when their superiors called them off the site.
Mr Henry said they were frustrated at the decision because they had not "fully explored the site''.
The inquest, before Coroner Gordon Matenga, will resume on December 3.
A total of 115 people died in the CTV Building collapse.
