Dr Coleman rejected that saying "it's pretty low that an absolute tragedy would be utilised by that member to try and make a political point".
Mr Goff reacted angrily saying Private Ross "happened to have been a family friend and I despise the minister for making that sort of accusation".
Asked again, Dr Coleman said Private Ross' death was "nothing to do with attrition and morale".
He said media reports of the inquiry's interim findings into Private Ross' death were correct.
"It looks like there were multiple safety failings in what is a very tragic case and my condolences go to the family because I think we would find there have been major errors which need to be corrected so this can never happen again."
He was awaiting the final report. Police had investigated the incident and a separate Ministry of Business Innovation and Employment investigation that could result in charges was also under way.
Fatal failures
• Labour's defence spokesman Phil Goff told Parliament the "catalogue of errors" that led to Private Ross's death included:
• The boat he was travelling in was not fully inflated, leading to him being thrown out of it.
• The boat's engine was not functioning correctly which meant it had difficulty returning to pick him up.
• The gas canister that would have inflated his life jacket was empty and hadn't been checked.
• The lifejacket he was wearing was a navy lifejacket and was unsuitable for use by army personnel.
• The safety boat was not accompanying the boat in which Private Ross was travelling.
• When the safety boat arrived it did not have the full complement of crew necessary to provide assistance.