Wales will face Australia, the Pacific Islands, Canada and New Zealand on consecutive weekends at the Millennium Stadium, Cardiff, next autumn.
They begin against the Wallabies on 4 November, repeating this year's pattern of playing four games rather than the traditional three.
That means players will have to be released back to their clubs for one of the matches, probably the Canada Test.
"We agreed Australia as an extra game," said WRU chief executive David Moffett.
"We have to keep playing these teams, the significant thing about Australia
is that they are in our World Cup group."
Over 300,000 fans streamed through the Millennium Stadium gates to watch Wales against New Zealand, Fiji, South Africa and Australia this November.
But the punishing schedule took a toll on the squad, with injury problems plaguing coach Mike Ruddock's side.
Their worst performance came as they scraped an 11-10 win over Fiji, the game in which Wales had released their English- and French-based players back to their clubs.
If that happens against Canada next year, it is likely to affect Wales' preparations for the following weekend's big All Blacks clash (25 November).
"That is what happens in the World Cup, you will have a hard game then an easier game," said Moffett, who leaves his post at the end of 2005 to live in New Zealand.
"You have to get on with it and we certainly did that this year.
"We were poor against New Zealand, ordinary against Fiji.
"We improved against South Africa and certainly improved again this week to beat Australia.
"That is a significant result because Australia did not have a poor team out there."