Grant Davidson told the families at an inquest in Auckland that he was sorry for the heartache that had resulted after the group was caught by sudden rising water levels in the Mangatepopo Gorge in the Tongariro National Park on April 15, 2008.
Mr Davidson apologised unreservedly, saying a series of slippages in the OPC's systems led to the tragedy, for which he accepted ultimate responsibility.
Mr Davidson is likely to be questioned on his statement tomorrow at the inquest, being conducted by coroner Christopher Devenport.
The six students -- Natasha Bray, Portia McPhail, Tara Gregory, Tom Hsu, Anthony Mulder and Floyd Fernandes -- and teacher Tony McClean were from Elim Christian College in Auckland.
On an outdoor adventure course, they were taken into the gorge by OPC instructor Jodie Sullivan.
Peter Zimmer, a contract instructor at the OPC that day, told the inquest today that better qualified and more experienced staff could have prevented their deaths.
Mr Devenport asked him what could be done differently at the centre to prevent a similar tragedy.
"If there were staff with higher qualifications who have worked in the industry for a number of years that would help," he replied.
"That would be better than someone who's just come out of polytech because judgment only comes over time." Mr Zimmer was in charge of another group that afternoon and said he regretted that he did not respond straight away when he became concerned for Ms Sullivan's group's safety.
Mr Devenport asked him why he did not go to the river until 4pm, despite becoming concerned for the group at about 1.30pm. "I was concerned at 1.30pm because I knew instructor Jodie Sullivan had the intention to take her group to the gorge," Mr Zimmer said.
"It was raining heavily and I knew if it continued to rain heavily conditions would change quickly. "My obligation was to my group, and I didn't know exactly if she was actually in the gorge. I wasn't 100 percent sure she was in the gorge until 4pm when I got a radio call.
The coroner asked why he did not leave his group with adequate supervision so he could assist in the emergency when lives were at risk.
"If there is life at risk I would drop everything and make sure the group was safe. I wish I could wind the clock back, and in hindsight I wish I'd gone into the gorge with field manager Kerry Palmer, and that certainly bugs me to this day," Mr Zimmer told the inquest.
Crown solicitor Ben Vanderkolk asked Mr Zimmer if he was waiting for managerial direction before he made a decision.
"It was my job to look after my group of students as their instructor on that day," he said.
Mr Vanderkolk asked if there was a contingency plan where staff at OPC shared information about weather warnings.
"There wasn't many occasions where there was a sharing of concerns about things such as river flows or conditions on the mountain," he said.
Mr Vanderkolk also asked if there was any rescue throw bag training for students before they went on the trip.
Mr Zimmer said it was standard practice to explain how a throw bag worked.
"Do you think it would have been daunting for them to be told they were going to be throw-bagged across the river?" Mr Vanderkolk asked.
Mr Zimmer said they would have had a briefing and a demonstration of the throw bag technique in a car park before they went into the gorge.
"Doing the throw bag demonstration in a car park is adequate for both children and adults, even foreigners with language difficulties," he told the inquest.
Mr Zimmer gave the coroner a demonstration of how a throw bag would be used in an emergency.
