Two Department of Conservation ground crews from Wanaka spent yesterday mopping up hot-spots left by the fire that swept through more than 100ha of tussock, scrub and beech forest above the East Matukituki River on Monday and Tuesday.
The fire is believed to have started on the East Matukituki track.
Conservation services manager Chris Sydney told the Otago Daily Times yesterday he did not want to pre-empt the department's formal investigation but it seemed ''fairly apparent'' the fire had been started by ''a guy who had a small campsite up there''.
The man is a New Zealander who spends some of his time in the Queenstown Lakes district.
Mr Sydney described him as ''a responsible sort of a guy'' who was ''fairly distressed''.
''Our intention is really just to give him a bit of space. He was certainly a bit shell-shocked [on Tuesday].''
Doc rural fire officer Jamie Cowan is carrying out the investigation and he declined to elaborate on what might have caused the fire.
He had still to speak to ''all the interested parties''.
''Obviously, we have assessed the site and spoken to one person of interest.''
Mr Cowan said the underlying fire danger in the park was ''not that high'' but there had been some very warm, windy days and ''very, very, low humidity''.
That meant that although the fire did not get into heavy, damp logs, it burned ''very fiercely in the very light fuels''.
A Doc spokeswoman said a permit is required for camp fires in the national park but not for the use of gas cookers.
Whenever total fire bans were imposed in the Upper Clutha region, the national park was included.
A total fire ban is not in place.
