Ireland lock Paul O'Connell and centre Gordon D'Arcy suffered hamstring strains in the World Cup victory over Australia and are a doubt for the Pool C clash against Russia, the team said on Monday.
D'Arcy limped off midway through the second half of the 15-6 win over the Tri-Nations champions at Eden Park on Saturday while British and Irish Lions captain O'Connell completed the whole match.
The Irish Rugby Football Union said in a statement that both players would be monitored over the next few days ahead of Friday's team announcement for the match against Russia in Rotorua on Sunday.
Ireland enjoyed a day off after arriving in Taupo ahead of their third Pool C match with the team still on a high after the surprise win over the Wallabies.
"There was an incredible buzz around the lads when we were setting off from Auckland," O'Connell's second row partner Donncha O'Callaghan said in the statement.
"You sort of expect that after a good win, but something we have all been chatting about is that we need to remain focused on the job at hand."
Ireland are likely to rest a number of first-team players for the match against Russia in preparation for their final Pool C game against Italy, where victory should mean they win the group and set up a probable quarter-final against Wales, Samoa or Fiji.
Ireland put behind them four August warm-up defeats and a sketchy performance in their opening World Cup win over the United States to stun the Wallabies with a powerful performance from their pack setting up the platform for victory.
O'Callaghan said it would be important Ireland maintain that level of intensity throughout the tournament.
"The work ethic was always very high over the last couple of months, but it was about making sure we did that work justice by delivering it on the pitch," O'Callaghan said.
"I think we managed to do that, but the challenge is now to keep the standards of our preparations up this week to reach the Russia game in as good a shape as possible."
Russia, competing in their first rugby World Cup, are expected to provide little resistance against Ireland and also have to cope with a short turnaround for the game as they face Italy in Nelson on Tuesday.
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