Wales will allow the Blues' stars to fly out late for the summer tour in order for them to feature in their region's Heineken Cup play-off. The Blues travel to face an Italian side, probably Calvisano, on the last weekend of May, with the winner taking a Heineken Cup spot next season.
Wales leave for North America on 27 May and coach Mike Ruddock is due to name his tour squad on 6 May.
The Blues are also checking the availability of their three Lions.
 | The regions all co-operated with our needs and we are happy to return the favour |
Sir Clive Woodward's side fly to New Zealand on 25 May, but the Welsh region hope that Gethin Jenkins, Tom Shanklin and Martyn Williams will be allowed to leave later. Ruddock says that getting the Blues into the Heineken Cup next season is important for Welsh rugby.
"The Heineken Cup is the top domestic competition in the northern hemisphere at the moment and it is the best way to prepare players for the international stage," said the Wales boss.
"Ideally, we'd like all our national players to be competing for their clubs and regions in the competition and we wish the Blues the very best of luck in their vital qualification match in Italy.
"The regions all co-operated with our needs by standing down players before our opening Six Nations match against England and we are happy to return the favour."
Ruddock - along with WRU general manager Steve Lewis and fitness coach Andrew Hore - has been holding talks with the regions with regards to the criteria laid out in the rugby charter.
 | The summer tour is a great chance for players on the fringe of the squad to compete for places in the side |
They hope to firm up agreements regarding matters as diverse as player fitness, national team training programmes and testing dates, player selection and nominations for national teams and player recruitment to regions. Ruddock says that his selections for Wales' summer trip to the USA and Canada will be crucial for the development of the national team.
"I have already held a number of meetings with staff from the Under-21 management team and senior selectors to discuss criteria and possible selection," said Ruddock.
"We will be looking at Premiership and regional games in Wales as well as games in England.
"While we have a strong, settled squad to work with, there is certainly an opportunity for young players making their mark to put their hands up.
"With so many players selected for the Lions, it is critical that we keep the team cohesion, consistency and level of success that we have worked so hard to achieve.
"It is a great chance for players on the fringe of the squad to compete for places in the side, particularly with a thrilling autumn series coming up against the three southern hemisphere superpowers."