Australia have retained top spot in the world rankings despite their defeat by New Zealand in the final of the 2014 Four Nations Series.
However, for the first time since the rankings were introduced in 2007, the Kangaroos' position is under threat and they will concede top spot to the Kiwis if Stephen Kearney's men win next year's Anzac Test and beat England on their three-match tour next autumn.
"We're very pleased with our progress this year and the Four Nations success was definitely a positive step forward," said Kearney.
"But we face some big challenges in the next 12 months - the Anzac Test against Australia and a tour of England - so we need to have to focus on maintaining and improving our levels of performance.
"If we can continue this development towards 2017, we will put ourselves in a great position to challenge for the 2017 World Cup title, which is our ultimate goal."
Among the other notable changes in the rankings, Samoa have climbed from seventh to fourth on the back of their impressive Four Nations debut and Scotland have moved into the top eight at the expense of Wales after winning the 2014 European Championships.
The positions are calculated using a formula which takes into account not just results but the rankings of opponents. While covering results over a five-year period, it adds greater weight to recent fixtures.
Samoa coach Matt Parish said: "I am very proud of our efforts over the past 12 months and it is a just reward for the time and effort put in by the players and management.
"I have no doubt that with the team I have on board now and more international games, that Samoa can beat one of the top three nations in the next three years, provided we get the necessary support."
Leading rankings (previous positions in brackets):
1 Australia (1), 2 New Zealand (2), 3 England (3), 4 Samoa (7), 5 France (4), 6 Fiji (5), 7 Ireland (10), 8 Scotland (11), 9 Wales (6), 10 USA (9), 11 Papua New Guinea (8), 12 Italy (12).