NWT ranked third in Canada last year for its overall 'investment attractiveness' and ninth in the world.
Nunavut ranked fourth in Canada and 11th in the world. Three years ago NWT placed seventh in Canada and Nunavut 10th.
The leading conservative institute has been surveying mining companies since 1997.
Its increasingly popular report assesses how government policy and procedures affect exploration investment in competing jurisdictions.
Mike Vaydik, general manager of the NWT/Nunavut Chamber of Mines, has been tracking the results since the survey began.
He notes that the best geology in the world won't attract investment if taxation or regulations make it tough too difficult to do business.
"Usually we do very well in the survey in terms of our mineral potential and are down somewhere in the middle of the pack in terms of policy and infrastructure," said Vaydik.
"Weighted together, we rate a little higher each year. That's encouraging and obviously we are doing something right."
Vaydik pointed to the time and cost of securing land use permits and transportation infrastructure as the biggest hurdles to investment in both territories.
"Infrastructure is easily one of the biggest disincentives to working up here," he said.
"I have had exploration managers with diamond companies tell me that they can drill nine holes in Alberta for the price of one hole in NWT.
"To which I always respond, 'Yes, but we have the diamonds."
Vaydik said the complaints the chamber hears most often from exploration firms inevitably involve excessive red tape or the cost of securing even low-level land use permits.
"We are getting better. Nunavut has started to introduce a 'single point of contact' application approval process, for example.
"It isn't perfect yet, but they are working on it. We need more of that kind of proactive approach."
The 2002 Fraser Institute survey drew input from 158 Canadian companies. The firms represented about 60 per cent of the $191 million US spent on exploration in the country in 2001.
The survey included all Canadian provinces and territories.
To compare determine investment attractiveness in different jurisdictions, public policy factors were weighted 40 per cent and mineral potential 60 per cent.
Chile claims the distinction as being the most attractive mining jurisdiction in the world, scoring 94 points out of 100.
Australia was next with 89 points and Nevada third with 86.
The losers were Wisconsin (13 points), Washington and New Zealand (22 points each), Nova Scotia and India (24 points each).
Quebec was the top-rated North American jurisdiction with 90 points.
The NWT scored 68 points and Nunavut 67.
Other top 10 jurisdictions for overall investment appeal are Peru (84), Brazil and Ontario (83 each), and Bolivia (68).
The 2002 survey was the first in six years in which British Columbia was not rated last for its mining policies.