At an inquest into the Sydney Grammar student's death, Deputy State Coroner Carl Milovanovich made a number of recommendations, including that the ambulance service, police, fire and Telstra call operators who answer triple-0 phone calls review the structure of their operations.

This inquest has identified that in all the calls David Iredale made to triple zero ... there was a lack of empathy and call takers lacked the skills ... to record vital information that was crucial," Mr Milovanovich said.

David, 17, died after becoming lost during a three-day hike in the Blue Mountains in December 2006.

He had believed the walk would count towards his silver Duke of Edinburgh award.

The coroner said David had died of severe hydration as a result of a "critical miscalculation" of the amount he and his two schoolfriends would need for a hike in the Blue Mountains.

David's body was found off the Mount Solitary track, close to the Kedumba River and the water he so desperately needed.

"David's death highlights just how dangerous ... the Australian bush can be," Mr Milovanovich said.

He also thanked David's parents for their role in assisting the inquest, telling them that the death of their son had pulled at his heart strings.

"To die of dehydration in bushland so close to water and only kilometres as the crow flies from civilisation ... only magnifies the extent of the tragedy," Mr Milovanovich said.

The coroner said among the issues to be considered should be whether there is a single state-wide call centre for all triple-0 calls, improved protocols for callers from remote locations to ensure there is no duplication in questions asked.

Mr Milovanovich said he was astonished that the Ambulance Service of NSW had not conducted a review or analysis of its performance following the teenager's death