wellington: New Zealand’s highly competitive Super Rugby derbies are beginning to take their toll on the teams, with the Auckland Blues coach Tana Umaga the worst hit as he scrambles to field a side missing 18 squad members through injury.

Super Rugby realigned this year to ensure more inter-conference action with the New Zealand section proving the most competitive, as coaches, fans and players have all admitted that intensity levels in those games are bordering on the extreme.

That level of passion has been hard to sustain for the Blues, who sit bottom of the conference after just two wins in seven matches, while Umaga has lost five players to season-ending injuries.

Two more, fullback Michael Collins (broken hand) and lock Josh Goodhue [shoulder], were ruled out for at least a month after their 24-10 over the Sunwolves in Tokyo on Saturday.

“It seems all the New Zealand Super teams are suffering from a high attrition rate and we are no different,” Umaga said in a statement on Tuesday. “It is testing the depth of the playing resources around the country.”

The Blues have played three New Zealand derbies and three matches against physical South African sides this season and now have seven midfield or outside backs and three locks unavailable for selection.

“It is testing our depth and our resources but at the same time it is giving opportunities to others,” added Umaga, whose side face the Otago Highlanders on Friday.

“It is challenging to build momentum when we are changing so many players and now bringing in new faces.”

The Waikato Chiefs have also suffered from similar issues with Aidan Ross the sixth player to be ruled out for the season after he picked up a serious ankle injury against the Wellington Hurricanes last week.

The Chiefs, who have now had all six props originally selected in their squad either ruled out for the season or still suffering from injury, have been forced to draft in Sam Prattley from club rugby.

“We’ve had a real challenge there, haven’t we?” Chiefs coach Colin Cooper said of their problems in the front row ahead of their clash with Australia’s Queensland Reds on Saturday.

“It’s just the way the game is, it’s fast, it’s physical, and yes, our expectation on front rowers is to do more than push.

“It’s a tough competition.”