The veteran centre accepted he will likely miss at least one of the All Blacks' four Tests on their UK tour as the 35-man party is rotated.
The 32-year-old is eyeing the matches against Wales and England with particular relish, but had no insight into Graham Henry's intentions.
He told The Dominion Post: "I don't think I've played four Tests in a row ever.
"You want to play the first few. Wales are the Six Nations champions so I want to play against them, and England, for being England. Who knows how it's going to work? I don't have a clue."
Umaga missed out on last season's Millennium Stadium encounter against the Welsh, a match the tourists won 26-25, but wants to play this time around.
"No one likes being told they're not playing that week," he added.
"You work hard to play but it's the harsh reality of the way the game is going now - it's so fast and so full of contact, it's just so tough."
Umaga started for Wellington at Eden Park last week, his first game since leading the All Blacks to the Tri-Nations title against Australia on the same ground.
"It's tough for the All Blacks because your eyes are always on what's happening later on and you have to mix that with what's happening now," he said.
"You have to prioritise and the All Blacks, well, you're playing for your country."
Umaga spoke as the NZRU announced their 2006 campaign.
New Zealand will host two home Bledisloe Cup games against Australia, but a match against the Pacific Islanders combined team has been shelved.
They also take on Ireland and South Africa.
Dunedin is not scheduled to see the All Blacks in 2006 but NZRU chief executive Steve Tew said the Union was looking for another match for the All Blacks in June, which if found, would be in Christchurch.
He said: "At the moment Dunedin is not scheduled to have an All Blacks Test match next year, but that is part of the normal annual allocation of matches.
"Otago hosted both a Lions match and the Tri-Nations match against South Africa this year."
The Pacific Island unions of Fiji, Samoa and Tonga have decided to ditch the combined XV concept to concentrate on their individual preparations for the 2007 World Cup.
"The All Blacks were originally scheduled to play the Pacific Islanders but the Pacific Islanders Rugby Alliance (PIRA) nations have asked if the game can be removed from the IRB schedule so they can prepare for the new IRB Pacific nations tournament and Rugby World Cup 2007," Tew said.