"The site is extremely hazardous and we've got oncoming winter approaching."
Winter was approaching, temperatures were becoming very cold and there were increasing uncertain weather patterns, he said.
"Operating at that altitude at such a hazardous site, we just can't afford to place the rescue crews in hazardous situations such as that.
"They've done everything that they can in order to recover any remains, they simply have not been able to."
A cockpit voice recorder had been recovered, which would be returned to Canadian authorities, Mr Ayres said.
He couldn't comment on the cause of the crash.
"The key is to get the voice recorder back and for that analysis to occur and the causes will be established then."
The men's next of kin had been informed.
Their bodies would be sent to New Zealand and from there returned to Canada.
The missing plane was equipped with survival equipment, including mountain tents, and supplies sufficient for five days.
It was owned and operated by Kenn Borek Air Ltd, a Canadian firm headquartered in Calgary that charters aircraft to the US programme.