The loss ended New Zealand's 18-match winning streak, the longest ever by a top-tier nation.
"I don't think you can ever say what any gap between north and south is because it depends who is playing each other," Charteris said in comments reported by Britain's Guardian newspaper.
"New Zealand are significantly ahead of South Africa and Australia and the task for the world is to catch them up. Ireland have shown that beating New Zealand is doable."
Charteris, who made his international debut against South Africa in 2004 and has played 70 tests, also felt that the gap between tier one and tier two nations was narrowing, highlighting Japan's unexpected win over South Africa at last year's Rugby World Cup.
"Teams like Japan, Romania and Georgia are closing the gap," the 33-year-old said.
"It is good to see so-called establishment teams coming unstuck and the beauty of the World Cup is that you face teams you do not meet very often."
Three years ago a weakened Wales lost to the Cherry Blossoms
in Tokyo. They face the same opponents in Cardiff on Saturday.
(Reporting by Debanjan Bose in Bengaluru; editing by Ken Ferris and John Stonestreet)
